diff --git a/CMakeLists.txt b/CMakeLists.txt
index d9632589c..4d2c469dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,638 +1,637 @@
 project(KWIN)
 set(PROJECT_VERSION "5.6.90")
 set(PROJECT_VERSION_MAJOR 5)
 
 cmake_minimum_required(VERSION 2.8.12 FATAL_ERROR)
 set(QT_MIN_VERSION "5.5.0")
 set(KF5_MIN_VERSION "5.12.0")
 
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules ${CMAKE_MODULE_PATH} )
 
 find_package(ECM 0.0.11 REQUIRED NO_MODULE)
 
 include(FeatureSummary)
 include(WriteBasicConfigVersionFile)
 include(GenerateExportHeader)
 
 # where to look first for cmake modules, before ${CMAKE_ROOT}/Modules/ is checked
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${ECM_MODULE_PATH} ${ECM_KDE_MODULE_DIR})
 
 find_package(Qt5 ${QT_MIN_VERSION} CONFIG REQUIRED COMPONENTS
     Concurrent
     Core
     DBus
     Quick
     QuickWidgets
     Script
     UiTools
     Widgets
     X11Extras
 )
 
 find_package(Qt5Test ${QT_MIN_VERSION} CONFIG QUIET)
 set_package_properties(Qt5Test PROPERTIES
          PURPOSE "Required for tests"
          TYPE OPTIONAL
          )
 add_feature_info("Qt5Test" Qt5Test_FOUND "Required for building tests")
 if (NOT Qt5Test_FOUND)
     set(BUILD_TESTING OFF CACHE BOOL "Build the testing tree.")
 endif()
 
 include(KDEInstallDirs)
 include(KDECMakeSettings)
 include(KDECompilerSettings NO_POLICY_SCOPE)
 
 include(ECMInstallIcons)
 include(ECMOptionalAddSubdirectory)
 
 add_definitions(-DQT_DISABLE_DEPRECATED_BEFORE=0 -DQT_USE_QSTRINGBUILDER)
 
 # require at least gcc 4.8
 if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
     if ("${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS "4.8")
         message(SEND_ERROR "Version ${CMAKE_CXX_COMPILER_VERSION} of the ${CMAKE_CXX_COMPILER_ID} C++ compiler is not supported. Please use version 4.8 or later.")
     endif()
 endif()
 
 find_package(Qt5Multimedia QUIET)
 set_package_properties(Qt5Multimedia PROPERTIES
          PURPOSE "Runtime-only dependency for effect video playback"
          TYPE RUNTIME
          )
 
 
 # required frameworks by Core
 find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
     Config
     ConfigWidgets
     CoreAddons
     Crash
     GlobalAccel
     I18n
     Init
     Notifications
     Package
     Plasma
     WidgetsAddons
     WindowSystem
     IconThemes
     IdleTime
 )
 # required frameworks by config modules
 find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
     Completion
     Declarative
     KCMUtils
     KIO
     NewStuff
     Service
     XmlGui
 )
 
 find_package(Threads)
 set_package_properties(Threads PROPERTIES
          PURPOSE "Needed for VirtualTerminal support in KWin Wayland"
          TYPE REQUIRED
          )
 
 # optional frameworks
 find_package(KF5Activities ${KF5_MIN_VERSION} CONFIG)
 set_package_properties(KF5Activities PROPERTIES
          PURPOSE "Enable building of KWin with kactivities support"
          TYPE OPTIONAL
          )
 add_feature_info("KF5Activities" KF5Activities_FOUND "Enable building of KWin with kactivities support")
 
 find_package(KF5DocTools ${KF5_MIN_VERSION} CONFIG)
 set_package_properties(KF5DocTools PROPERTIES
          PURPOSE "Enable building documentation"
          TYPE OPTIONAL
          )
 add_feature_info("KF5DocTools" KF5DocTools_FOUND "Enable building documentation")
 
 find_package(KDecoration2 CONFIG REQUIRED)
 find_package(KF5Wayland CONFIG REQUIRED)
 set_package_properties(KF5Wayland PROPERTIES
                        TYPE REQUIRED
                       )
 
 find_package(KScreenLocker CONFIG REQUIRED)
 set_package_properties(KScreenLocker PROPERTIES
                        TYPE REQUIRED
                        PURPOSE "For screenlocker integration in kwin_wayland")
 
 find_package(Breeze ${PROJECT_VERSION} CONFIG)
 set_package_properties(Breeze PROPERTIES
                        TYPE OPTIONAL
                        PURPOSE "For setting the default window decoration plugin")
 if(${Breeze_FOUND})
     if(${BREEZE_WITH_KDECORATION})
         set(HAVE_BREEZE_DECO true)
     else()
         set(HAVE_BREEZE_DECO FALSE)
     endif()
 else()
     set(HAVE_BREEZE_DECO FALSE)
 endif()
 add_feature_info("Breeze-Decoration" HAVE_BREEZE_DECO "Default decoration plugin Breeze")
 
 find_package(EGL)
 set_package_properties(EGL PROPERTIES
                        TYPE RUNTIME
                        PURPOSE "Required to build KWin with EGL support"
                       )
 
 find_package(epoxy)
 set_package_properties(epoxy PROPERTIES DESCRIPTION "libepoxy"
                        URL "http://github.com/anholt/libepoxy"
                        TYPE REQUIRED
                        PURPOSE "OpenGL dispatch library"
                       )
 
 find_package(Wayland 1.2 REQUIRED COMPONENTS Cursor OPTIONAL_COMPONENTS Egl)
 set_package_properties(Wayland PROPERTIES
                        TYPE REQUIRED
                        PURPOSE "Required for building KWin with Wayland support"
                       )
 add_feature_info("Wayland::EGL" Wayland_Egl_FOUND "Enable building of Wayland backend and QPA with EGL support.")
 set(HAVE_WAYLAND_EGL FALSE)
 if(Wayland_Egl_FOUND)
     set(HAVE_WAYLAND_EGL TRUE)
 endif()
 
 find_package(XKB 0.4.1)
 set_package_properties(XKB PROPERTIES
                        TYPE REQUIRED
                        PURPOSE "Required for building KWin with Wayland support"
                       )
 
 find_package(Libinput 0.10)
 set_package_properties(Libinput PROPERTIES TYPE OPTIONAL PURPOSE "Required for input handling on Wayland.")
 
 find_package(UDev)
 set_package_properties(UDev PROPERTIES  URL "http://www.freedesktop.org/software/systemd/libudev/"
                                         DESCRIPTION "Linux device library."
                                         TYPE OPTIONAL
                                         PURPOSE "Required for input handling on Wayland."
                         )
 set(HAVE_INPUT FALSE)
 if (Libinput_FOUND AND UDEV_FOUND)
     set(HAVE_INPUT TRUE)
 endif()
 
 find_package(Libdrm)
 set_package_properties(Libdrm PROPERTIES TYPE OPTIONAL PURPOSE "Required for drm output on Wayland.")
 set(HAVE_DRM FALSE)
 if(Libdrm_FOUND AND UDEV_FOUND)
     set(HAVE_DRM TRUE)
 endif()
 
 find_package(gbm)
 set_package_properties(gbm PROPERTIES TYPE OPTIONAL PURPOSE "Required for egl ouput of drm backend.")
 set(HAVE_GBM FALSE)
 if(HAVE_DRM AND gbm_FOUND)
     set(HAVE_GBM TRUE)
 endif()
 
 find_package(libhybris)
 set_package_properties(libhybris PROPERTIES TYPE OPTIONAL PURPOSE "Required for libhybris backend")
 set(HAVE_LIBHYBRIS ${libhybris_FOUND})
 
 find_package(X11)
 set_package_properties(X11 PROPERTIES DESCRIPTION "X11 libraries"
                         URL "http://www.x.org"
                         TYPE REQUIRED
                     )
 add_feature_info("XInput" X11_Xinput_FOUND "Required for poll-free mouse cursor updates")
 set(HAVE_X11_XINPUT ${X11_Xinput_FOUND})
 
 # All the required XCB components
 find_package(XCB 1.10
     REQUIRED COMPONENTS
         XCB
         XFIXES
         DAMAGE
         COMPOSITE
         SHAPE
         SYNC
         RENDER
         RANDR
         KEYSYMS
         IMAGE
         SHM
         GLX
         CURSOR
     OPTIONAL_COMPONENTS
         ICCCM
 )
 set_package_properties(XCB PROPERTIES TYPE REQUIRED)
 
 # and the optional XCB dependencies
 if (XCB_ICCCM_VERSION VERSION_LESS "0.4")
     set(XCB_ICCCM_FOUND FALSE)
 endif()
 add_feature_info("XCB-ICCCM" XCB_ICCCM_FOUND "Required for building test applications for KWin")
 
 find_package(X11_XCB)
 set_package_properties(X11_XCB PROPERTIES
                        PURPOSE "Required for building X11 windowed backend of kwin_wayland"
                        TYPE OPTIONAL)
 
 # dependencies for QPA plugin
 find_package(Qt5PlatformSupport REQUIRED)
 find_package(Freetype REQUIRED)
 set_package_properties(Freetype PROPERTIES DESCRIPTION "A font rendering engine"
                        URL "http://www.freetype.org"
                        TYPE REQUIRED
                        PURPOSE "Needed for KWin's QPA plugin."
                       )
 find_package(Fontconfig REQUIRED)
 set_package_properties(Fontconfig PROPERTIES DESCRIPTION "Font access configuration library"
                        URL "http://www.freedesktop.org/wiki/Software/fontconfig"
                        TYPE REQUIRED
                        PURPOSE "Needed for KWin's QPA plugin."
                       )
 
 find_package(Xwayland)
 set_package_properties(Xwayland PROPERTIES
     URL "http://x.org"
     DESCRIPTION "Xwayland X server"
     TYPE RUNTIME
     PURPOSE "Needed for running kwin_wayland"
     )
 
 ########### configure tests ###############
 include(CMakeDependentOption)
 
 option(KWIN_BUILD_DECORATIONS "Enable building of KWin decorations." ON)
 option(KWIN_BUILD_KCMS "Enable building of KWin configuration modules." ON)
 option(KWIN_BUILD_TABBOX "Enable building of KWin Tabbox functionality" ON)
 option(KWIN_BUILD_XRENDER_COMPOSITING "Enable building of KWin with XRender Compositing support" ON)
 cmake_dependent_option(KWIN_BUILD_ACTIVITIES "Enable building of KWin with kactivities support" ON "KF5Activities_FOUND" OFF)
 
 # Binary name of KWin
 set(KWIN_NAME "kwin")
 set(KWIN_INTERNAL_NAME_X11 "kwin_x11")
 set(KWIN_INTERNAL_NAME_WAYLAND "kwin_wayland")
 set(KWIN_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 # KWIN_HAVE_XRENDER_COMPOSITING - whether XRender-based compositing support is available: may be disabled
 if( KWIN_BUILD_XRENDER_COMPOSITING )
     set( KWIN_HAVE_XRENDER_COMPOSITING 1 )
 endif()
 
 include_directories(${XKB_INCLUDE_DIR})
 
 include_directories(${epoxy_INCLUDE_DIR})
 set(HAVE_EPOXY_GLX ${epoxy_HAS_GLX})
 
 # for things that are also used by kwin libraries
 configure_file(libkwineffects/kwinconfig.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/libkwineffects/kwinconfig.h )
 # for kwin internal things
 set(HAVE_X11_XCB ${X11_XCB_FOUND})
 
 include(CheckIncludeFile)
 include(CheckIncludeFiles)
 include(CheckSymbolExists)
 check_include_files(unistd.h HAVE_UNISTD_H)
 check_include_files(malloc.h HAVE_MALLOC_H)
 
 check_include_file("sys/prctl.h" HAVE_SYS_PRCTL_H)
 check_symbol_exists(PR_SET_DUMPABLE "sys/prctl.h" HAVE_PR_SET_DUMPABLE)
 check_include_file("sys/procctl.h" HAVE_SYS_PROCCTL_H)
 check_symbol_exists(PROC_TRACE_CTL "sys/procctl.h" HAVE_PROC_TRACE_CTL)
 if (HAVE_PR_SET_DUMPABLE OR HAVE_PROC_TRACE_CTL)
     set(CAN_DISABLE_PTRACE TRUE)
 endif()
 add_feature_info("prctl/procctl tracing control"
                  CAN_DISABLE_PTRACE
                  "Required for disallowing ptrace on kwin_wayland process")
 
 configure_file(config-kwin.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/config-kwin.h )
 
 
 ########### global ###############
 set(kwin_effects_dbus_xml ${CMAKE_CURRENT_SOURCE_DIR}/org.kde.kwin.Effects.xml)
 
 include_directories(BEFORE
     ${CMAKE_CURRENT_BINARY_DIR}/libkwineffects
     ${CMAKE_CURRENT_BINARY_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/libkwineffects
     ${CMAKE_CURRENT_SOURCE_DIR}/effects
     ${CMAKE_CURRENT_SOURCE_DIR}/tabbox
     )
 
 add_subdirectory( libkwineffects )
 add_subdirectory( killer )
 if(KWIN_BUILD_KCMS)
     add_subdirectory( kcmkwin )
 endif()
 
 add_subdirectory( data )
 
 add_subdirectory( effects )
 add_subdirectory( scripts )
 add_subdirectory( tabbox )
 add_subdirectory(scripting)
 
 add_definitions(-DKDE_DEFAULT_DEBUG_AREA=1212)
 
 ########### next target ###############
 
 set(kwin_KDEINIT_SRCS
    workspace.cpp 
    dbusinterface.cpp
    abstract_client.cpp
    client.cpp 
    client_machine.cpp
    cursor.cpp
    debug_console.cpp
    tabgroup.cpp
    focuschain.cpp
    globalshortcuts.cpp
    input.cpp
    keyboard_input.cpp
    pointer_input.cpp
    touch_input.cpp
    netinfo.cpp
    placement.cpp 
    atoms.cpp 
    utils.cpp 
    layers.cpp 
    main.cpp 
    options.cpp 
    outline.cpp
    events.cpp 
    killwindow.cpp 
    geometrytip.cpp 
    screens.cpp
    shadow.cpp
    sm.cpp 
    group.cpp 
    manage.cpp 
    overlaywindow.cpp
    activation.cpp 
    useractions.cpp 
    geometry.cpp 
    rules.cpp
    composite.cpp
    toplevel.cpp
    unmanaged.cpp
    scene.cpp
    scene_xrender.cpp
    scene_opengl.cpp
    scene_qpainter.cpp
    thumbnailitem.cpp
    lanczosfilter.cpp
    deleted.cpp
    effects.cpp
    effectloader.cpp
-   compositingprefs.cpp
    virtualdesktops.cpp
    xcbutils.cpp
    x11eventfilter.cpp
    logind.cpp
     screenedge.cpp
     scripting/scripting.cpp
     scripting/workspace_wrapper.cpp
     scripting/meta.cpp
     scripting/scriptedeffect.cpp
     scripting/scriptingutils.cpp
     scripting/timer.cpp
     scripting/scripting_model.cpp
     scripting/dbuscall.cpp
     scripting/screenedgeitem.cpp
     scripting/scripting_logging.cpp
     decorations/decoratedclient.cpp
     decorations/decorationbridge.cpp
     decorations/decorationpalette.cpp
     decorations/settings.cpp
     decorations/decorationrenderer.cpp
     decorations/decorations_logging.cpp
     abstract_egl_backend.cpp
     platform.cpp
     shell_client.cpp
     wayland_server.cpp
     wayland_cursor_theme.cpp
    )
 
 if(KWIN_BUILD_TABBOX)
     set(
         kwin_KDEINIT_SRCS ${kwin_KDEINIT_SRCS}
         tabbox/tabbox.cpp
         tabbox/clientmodel.cpp
         tabbox/desktopchain.cpp
         tabbox/desktopmodel.cpp
         tabbox/switcheritem.cpp
         tabbox/tabboxconfig.cpp
         tabbox/tabboxhandler.cpp
         tabbox/tabbox_logging.cpp
   )
 endif()
 
 if(KWIN_BUILD_ACTIVITIES)
     set(
         kwin_KDEINIT_SRCS ${kwin_KDEINIT_SRCS}
         activities.cpp
     )
 endif()
 
 if(UDEV_FOUND)
     set(kwin_KDEINIT_SRCS
         ${kwin_KDEINIT_SRCS}
         udev.cpp
     )
 endif()
 
 if(HAVE_INPUT)
     set(kwin_KDEINIT_SRCS
         ${kwin_KDEINIT_SRCS}
         libinput/context.cpp
         libinput/connection.cpp
         libinput/device.cpp
         libinput/events.cpp
         libinput/libinput_logging.cpp
         virtual_terminal.cpp
     )
 endif()
 
 kconfig_add_kcfg_files(kwin_KDEINIT_SRCS settings.kcfgc)
 
 qt5_add_dbus_adaptor( kwin_KDEINIT_SRCS org.kde.KWin.xml dbusinterface.h KWin::DBusInterface )
 qt5_add_dbus_adaptor( kwin_KDEINIT_SRCS org.kde.kwin.Compositing.xml dbusinterface.h KWin::CompositorDBusInterface )
 qt5_add_dbus_adaptor( kwin_KDEINIT_SRCS ${kwin_effects_dbus_xml} effects.h KWin::EffectsHandlerImpl )
 
 qt5_add_dbus_interface( kwin_KDEINIT_SRCS ${CMAKE_CURRENT_SOURCE_DIR}/org.freedesktop.ScreenSaver.xml screenlocker_interface)
 
 qt5_add_resources( kwin_KDEINIT_SRCS resources.qrc )
 
 ki18n_wrap_ui(kwin_KDEINIT_SRCS
     debug_console.ui
     shortcutdialog.ui
 )
 
 ########### target link libraries ###############
 
 set(kwin_OWN_LIBS
     kwineffects
     kwinxrenderutils
     kwin4_effect_builtins
 )
 
 set(kwin_QT_LIBS
     Qt5::Concurrent
     Qt5::DBus
     Qt5::Quick
     Qt5::Script
     Qt5::X11Extras
 )
 
 set(kwin_KDE_LIBS
     KF5::ConfigCore
     KF5::CoreAddons
     KF5::ConfigWidgets
     KF5::GlobalAccel
     KF5::GlobalAccelPrivate
     KF5::I18n
     KF5::Notifications
     KF5::Package
     KF5::Plasma
     KF5::WindowSystem
     KDecoration2::KDecoration
     KDecoration2::KDecoration2Private
     PW::KScreenLocker
 )
 
 set(kwin_XLIB_LIBS
     ${X11_X11_LIB}
     ${X11_ICE_LIB}
     ${X11_SM_LIB}
 )
 
 if(X11_Xinput_FOUND)
     set(kwin_XLIB_LIBS ${kwin_XLIB_LIBS} ${X11_Xinput_LIB})
 endif()
 
 set(kwin_XCB_LIBS
     XCB::XCB
     XCB::XFIXES
     XCB::DAMAGE
     XCB::COMPOSITE
     XCB::SHAPE
     XCB::SYNC
     XCB::RENDER
     XCB::RANDR
     XCB::KEYSYMS
     XCB::SHM
     XCB::GLX
     XCB::CURSOR
 )
 
 set(kwin_WAYLAND_LIBS
     XKB::XKB
     KF5::WaylandClient
     KF5::WaylandServer
     Wayland::Cursor
     ${CMAKE_THREAD_LIBS_INIT}
 )
 
 if(KWIN_BUILD_ACTIVITIES)
     set(kwin_KDE_LIBS ${kwin_KDE_LIBS} KF5::Activities)
 endif()
 
 set(kwinLibs
     ${kwin_OWN_LIBS}
     ${kwin_QT_LIBS}
     ${kwin_KDE_LIBS}
     ${kwin_XLIB_LIBS}
     ${kwin_XCB_LIBS}
     ${kwin_WAYLAND_LIBS}
 )
 
 if(UDEV_FOUND)
     set(kwinLibs ${kwinLibs} ${UDEV_LIBS})
 endif()
 
 if(HAVE_INPUT)
     set(kwinLibs ${kwinLibs} Libinput::Libinput)
 endif()
 
 add_library(kwin SHARED ${kwin_KDEINIT_SRCS})
 
 set_target_properties(kwin PROPERTIES
    VERSION ${PROJECT_VERSION}
    SOVERSION ${PROJECT_VERSION_MAJOR}
    )
 
 target_link_libraries(kwin ${kwinLibs})
 generate_export_header(kwin EXPORT_FILE_NAME kwin_export.h)
 
 target_link_libraries(kwin kwinglutils ${epoxy_LIBRARY})
 # -ldl used by OpenGL code
 find_library(DL_LIBRARY dl)
 if (DL_LIBRARY)
 target_link_libraries(kwin ${DL_LIBRARY})
 endif()
 
 kf5_add_kdeinit_executable(kwin_x11 main_x11.cpp)
 target_link_libraries(kdeinit_kwin_x11 kwin KF5::Crash)
 
 install(TARGETS kwin             ${INSTALL_TARGETS_DEFAULT_ARGS} LIBRARY NAMELINK_SKIP )
 install(TARGETS kdeinit_kwin_x11 ${INSTALL_TARGETS_DEFAULT_ARGS} )
 install(TARGETS kwin_x11         ${INSTALL_TARGETS_DEFAULT_ARGS} )
 
 add_executable(kwin_wayland main_wayland.cpp)
 target_link_libraries(kwin_wayland kwin)
 
 install(TARGETS kwin_wayland         ${INSTALL_TARGETS_DEFAULT_ARGS} )
 
 add_subdirectory(plugins)
 
 ########### install files ###############
 
 install( FILES kwin.kcfg  DESTINATION  ${KCFG_INSTALL_DIR} RENAME ${KWIN_NAME}.kcfg )
 install( FILES kwin.notifyrc  DESTINATION  ${KNOTIFYRC_INSTALL_DIR} RENAME ${KWIN_NAME}.notifyrc)
 install(
     FILES
         org.kde.KWin.xml
         org.kde.kwin.Compositing.xml
         org.kde.kwin.Effects.xml
     DESTINATION
         ${KDE_INSTALL_DBUSINTERFACEDIR}
 )
 install( FILES ${CMAKE_CURRENT_BINARY_DIR}/kwin_export.h DESTINATION ${INCLUDE_INSTALL_DIR} COMPONENT Devel)
 
 # Install the KWin/Script service type
 install( FILES scripting/kwinscript.desktop DESTINATION ${SERVICETYPES_INSTALL_DIR} )
 
 ecm_install_icons(
     ICONS
         16-apps-kwin.png
         32-apps-kwin.png
         48-apps-kwin.png
         sc-apps-kwin.svgz
     DESTINATION
         ${ICON_INSTALL_DIR}
     THEME
         hicolor
 )
 
 add_subdirectory(qml)
 add_subdirectory(autotests)
 add_subdirectory(tests)
 
 if (KF5DocTools_FOUND)
     add_subdirectory(doc)
 endif()
 
 feature_summary(WHAT ALL INCLUDE_QUIET_PACKAGES FATAL_ON_MISSING_REQUIRED_PACKAGES)
 
 include(ECMPackageConfigHelpers)
 set(CMAKECONFIG_INSTALL_DIR "${CMAKECONFIG_INSTALL_PREFIX}/KWinDBusInterface")
 ecm_configure_package_config_file(KWinDBusInterfaceConfig.cmake.in
     "${CMAKE_CURRENT_BINARY_DIR}/KWinDBusInterfaceConfig.cmake"
     PATH_VARS KDE_INSTALL_DBUSINTERFACEDIR
     INSTALL_DESTINATION ${CMAKECONFIG_INSTALL_DIR})
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/KWinDBusInterfaceConfig.cmake
     DESTINATION ${CMAKECONFIG_INSTALL_DIR})
diff --git a/composite.cpp b/composite.cpp
index 7b0a166f4..77163635d 100644
--- a/composite.cpp
+++ b/composite.cpp
@@ -1,1330 +1,1329 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2006 Lubos Lunak <l.lunak@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "composite.h"
 
 #include "dbusinterface.h"
 #include "utils.h"
 #include <QTextStream>
 #include "workspace.h"
 #include "client.h"
 #include "unmanaged.h"
 #include "deleted.h"
 #include "effects.h"
 #include "overlaywindow.h"
 #include "scene.h"
 #include "scene_xrender.h"
 #include "scene_opengl.h"
 #include "scene_qpainter.h"
 #include "screens.h"
 #include "shadow.h"
 #include "useractions.h"
-#include "compositingprefs.h"
 #include "xcbutils.h"
 #include "platform.h"
 #include "shell_client.h"
 #include "wayland_server.h"
 #include "decorations/decoratedclient.h"
 
 #include <KWayland/Server/surface_interface.h>
 
 #include <stdio.h>
 
 #include <QtConcurrentRun>
 #include <QFutureWatcher>
 #include <QMenu>
 #include <QTimerEvent>
 #include <QDateTime>
 #include <QOpenGLContext>
 #include <KGlobalAccel>
 #include <KLocalizedString>
 #include <KNotification>
 #include <KSelectionWatcher>
 
 #include <xcb/composite.h>
 #include <xcb/damage.h>
 
 Q_DECLARE_METATYPE(KWin::Compositor::SuspendReason)
 
 namespace KWin
 {
 
 extern int currentRefreshRate();
 
 CompositorSelectionOwner::CompositorSelectionOwner(const char *selection) : KSelectionOwner(selection, connection(), rootWindow()), owning(false)
 {
     connect (this, SIGNAL(lostOwnership()), SLOT(looseOwnership()));
 }
 
 void CompositorSelectionOwner::looseOwnership()
 {
     owning = false;
 }
 
 KWIN_SINGLETON_FACTORY_VARIABLE(Compositor, s_compositor)
 
 static inline qint64 milliToNano(int milli) { return qint64(milli) * 1000 * 1000; }
 static inline qint64 nanoToMilli(int nano) { return nano / (1000*1000); }
 
 Compositor::Compositor(QObject* workspace)
     : QObject(workspace)
     , m_suspended(options->isUseCompositing() ? NoReasonSuspend : UserSuspend)
     , cm_selection(NULL)
     , vBlankInterval(0)
     , fpsInterval(0)
     , m_xrrRefreshRate(0)
     , forceUnredirectCheck(false)
     , m_finishing(false)
     , m_timeSinceLastVBlank(0)
     , m_scene(NULL)
     , m_bufferSwapPending(false)
     , m_composeAtSwapCompletion(false)
 {
     qRegisterMetaType<Compositor::SuspendReason>("Compositor::SuspendReason");
     connect(&unredirectTimer, SIGNAL(timeout()), SLOT(delayedCheckUnredirect()));
     connect(&compositeResetTimer, SIGNAL(timeout()), SLOT(restart()));
     connect(options, &Options::configChanged, this, &Compositor::slotConfigChanged);
     connect(options, SIGNAL(unredirectFullscreenChanged()), SLOT(delayedCheckUnredirect()));
     unredirectTimer.setSingleShot(true);
     compositeResetTimer.setSingleShot(true);
     nextPaintReference.invalidate(); // Initialize the timer
 
     // 2 sec which should be enough to restart the compositor
     static const int compositorLostMessageDelay = 2000;
 
     m_releaseSelectionTimer.setSingleShot(true);
     m_releaseSelectionTimer.setInterval(compositorLostMessageDelay);
     connect(&m_releaseSelectionTimer, SIGNAL(timeout()), SLOT(releaseCompositorSelection()));
 
     m_unusedSupportPropertyTimer.setInterval(compositorLostMessageDelay);
     m_unusedSupportPropertyTimer.setSingleShot(true);
     connect(&m_unusedSupportPropertyTimer, SIGNAL(timeout()), SLOT(deleteUnusedSupportProperties()));
 
     // delay the call to setup by one event cycle
     // The ctor of this class is invoked from the Workspace ctor, that means before
     // Workspace is completely constructed, so calling Workspace::self() would result
     // in undefined behavior. This is fixed by using a delayed invocation.
     if (kwinApp()->platform()->isReady()) {
         QMetaObject::invokeMethod(this, "setup", Qt::QueuedConnection);
     }
     connect(kwinApp()->platform(), &Platform::readyChanged, this,
         [this] (bool ready) {
             if (ready) {
                 setup();
             } else {
                 finish();
             }
         }, Qt::QueuedConnection
     );
     connect(kwinApp(), &Application::x11ConnectionAboutToBeDestroyed, this,
         [this] {
             delete cm_selection;
             cm_selection = nullptr;
         }
     );
 
     // register DBus
     new CompositorDBusInterface(this);
 }
 
 Compositor::~Compositor()
 {
     emit aboutToDestroy();
     finish();
     deleteUnusedSupportProperties();
     delete cm_selection;
     s_compositor = NULL;
 }
 
 
 void Compositor::setup()
 {
     if (hasScene())
         return;
     if (m_suspended) {
         QStringList reasons;
         if (m_suspended & UserSuspend) {
             reasons << QStringLiteral("Disabled by User");
         }
         if (m_suspended & BlockRuleSuspend) {
             reasons << QStringLiteral("Disabled by Window");
         }
         if (m_suspended & ScriptSuspend) {
             reasons << QStringLiteral("Disabled by Script");
         }
         qCDebug(KWIN_CORE) << "Compositing is suspended, reason:" << reasons;
         return;
-    } else if (!CompositingPrefs::compositingPossible()) {
+    } else if (!kwinApp()->platform()->compositingPossible()) {
         qCCritical(KWIN_CORE) << "Compositing is not possible";
         return;
     }
     m_starting = true;
 
     if (!options->isCompositingInitialized()) {
         options->reloadCompositingSettings(true);
         slotCompositingOptionsInitialized();
     } else {
         slotCompositingOptionsInitialized();
     }
 }
 
 extern int screen_number; // main.cpp
 extern bool is_multihead;
 
 void Compositor::slotCompositingOptionsInitialized()
 {
     claimCompositorSelection();
 
     // There might still be a deleted around, needs to be cleared before creating the scene (BUG 333275)
     if (Workspace::self()) {
         while (!Workspace::self()->deletedList().isEmpty()) {
             Workspace::self()->deletedList().first()->discard();
         }
     }
 
     switch(options->compositingMode()) {
     case OpenGLCompositing: {
         qCDebug(KWIN_CORE) << "Initializing OpenGL compositing";
 
         // Some broken drivers crash on glXQuery() so to prevent constant KWin crashes:
         KSharedConfigPtr unsafeConfigPtr = kwinApp()->config();
         KConfigGroup unsafeConfig(unsafeConfigPtr, "Compositing");
         const QString openGLIsUnsafe = QLatin1String("OpenGLIsUnsafe") + (is_multihead ? QString::number(screen_number) : QString());
         if (unsafeConfig.readEntry(openGLIsUnsafe, false))
             qCWarning(KWIN_CORE) << "KWin has detected that your OpenGL library is unsafe to use";
         else {
             unsafeConfig.writeEntry(openGLIsUnsafe, true);
             unsafeConfig.sync();
-            if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGL && !kwinApp()->shouldUseWaylandForCompositing() && !CompositingPrefs::hasGlx()) {
+            if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGL && !kwinApp()->shouldUseWaylandForCompositing() && !Xcb::Extensions::self()->hasGlx()) {
                 unsafeConfig.writeEntry(openGLIsUnsafe, false);
                 unsafeConfig.sync();
                 qCDebug(KWIN_CORE) << "No glx extensions available";
                 break;
             }
 
             m_scene = SceneOpenGL::createScene(this);
 
             // TODO: Add 30 second delay to protect against screen freezes as well
             unsafeConfig.writeEntry(openGLIsUnsafe, false);
             unsafeConfig.sync();
 
             if (m_scene && !m_scene->initFailed()) {
                 connect(static_cast<SceneOpenGL*>(m_scene), &SceneOpenGL::resetCompositing, this, &Compositor::restart);
                 break; // -->
             }
             delete m_scene;
             m_scene = NULL;
         }
 
         // Do not Fall back to XRender - it causes problems when selfcheck fails during startup, but works later on
         break;
     }
 #ifdef KWIN_HAVE_XRENDER_COMPOSITING
     case XRenderCompositing:
         qCDebug(KWIN_CORE) << "Initializing XRender compositing";
         m_scene = SceneXrender::createScene(this);
         break;
 #endif
     case QPainterCompositing:
         qCDebug(KWIN_CORE) << "Initializing QPainter compositing";
         m_scene = SceneQPainter::createScene(this);
         break;
     default:
         qCDebug(KWIN_CORE) << "No compositing enabled";
         m_starting = false;
         if (cm_selection) {
             cm_selection->owning = false;
             cm_selection->release();
         }
         if (kwinApp()->platform()->requiresCompositing()) {
             qCCritical(KWIN_CORE) << "The used windowing system requires compositing";
             qCCritical(KWIN_CORE) << "We are going to quit KWin now as it is broken";
             qApp->quit();
         }
         return;
     }
     if (m_scene == NULL || m_scene->initFailed()) {
         qCCritical(KWIN_CORE) << "Failed to initialize compositing, compositing disabled";
         delete m_scene;
         m_scene = NULL;
         m_starting = false;
         if (cm_selection) {
             cm_selection->owning = false;
             cm_selection->release();
         }
         if (kwinApp()->platform()->requiresCompositing()) {
             qCCritical(KWIN_CORE) << "The used windowing system requires compositing";
             qCCritical(KWIN_CORE) << "We are going to quit KWin now as it is broken";
             qApp->quit();
         }
         return;
     }
     emit sceneCreated();
 
     if (Workspace::self()) {
         startupWithWorkspace();
     } else {
         connect(kwinApp(), &Application::workspaceCreated, this, &Compositor::startupWithWorkspace);
     }
 }
 
 void Compositor::claimCompositorSelection()
 {
     if (!cm_selection && kwinApp()->x11Connection()) {
         char selection_name[ 100 ];
         sprintf(selection_name, "_NET_WM_CM_S%d", Application::x11ScreenNumber());
         cm_selection = new CompositorSelectionOwner(selection_name);
         connect(cm_selection, SIGNAL(lostOwnership()), SLOT(finish()));
     }
 
     if (!cm_selection) // no X11 yet
         return;
 
     if (!cm_selection->owning) {
         cm_selection->claim(true);   // force claiming
         cm_selection->owning = true;
     }
 }
 
 void Compositor::startupWithWorkspace()
 {
     if (!m_starting) {
         return;
     }
     Q_ASSERT(m_scene);
     claimCompositorSelection();
     m_xrrRefreshRate = KWin::currentRefreshRate();
     fpsInterval = options->maxFpsInterval();
     if (m_scene->syncsToVBlank()) {  // if we do vsync, set the fps to the next multiple of the vblank rate
         vBlankInterval = milliToNano(1000) / m_xrrRefreshRate;
         fpsInterval = qMax((fpsInterval / vBlankInterval) * vBlankInterval, vBlankInterval);
     } else
         vBlankInterval = milliToNano(1); // no sync - DO NOT set "0", would cause div-by-zero segfaults.
     m_timeSinceLastVBlank = fpsInterval - (options->vBlankTime() + 1); // means "start now" - we don't have even a slight idea when the first vsync will occur
     scheduleRepaint();
     xcb_composite_redirect_subwindows(connection(), rootWindow(), XCB_COMPOSITE_REDIRECT_MANUAL);
     new EffectsHandlerImpl(this, m_scene);   // sets also the 'effects' pointer
     connect(Workspace::self(), &Workspace::deletedRemoved, m_scene, &Scene::windowDeleted);
     connect(effects, SIGNAL(screenGeometryChanged(QSize)), SLOT(addRepaintFull()));
     addRepaintFull();
     foreach (Client * c, Workspace::self()->clientList()) {
         c->setupCompositing();
         c->getShadow();
     }
     foreach (Client * c,  Workspace::self()->desktopList())
         c->setupCompositing();
     foreach (Unmanaged * c, Workspace::self()->unmanagedList()) {
         c->setupCompositing();
         c->getShadow();
     }
 
     emit compositingToggled(true);
 
     m_starting = false;
     if (m_releaseSelectionTimer.isActive()) {
         m_releaseSelectionTimer.stop();
     }
 
     // render at least once
     performCompositing();
 }
 
 void Compositor::scheduleRepaint()
 {
     if (!compositeTimer.isActive())
         setCompositeTimer();
 }
 
 void Compositor::finish()
 {
     if (!hasScene())
         return;
     m_finishing = true;
     m_releaseSelectionTimer.start();
     if (Workspace::self()) {
         foreach (Client * c, Workspace::self()->clientList())
             m_scene->windowClosed(c, NULL);
         foreach (Client * c, Workspace::self()->desktopList())
             m_scene->windowClosed(c, NULL);
         foreach (Unmanaged * c, Workspace::self()->unmanagedList())
             m_scene->windowClosed(c, NULL);
         foreach (Deleted * c, Workspace::self()->deletedList())
             m_scene->windowDeleted(c);
         foreach (Client * c, Workspace::self()->clientList())
         c->finishCompositing();
         foreach (Client * c, Workspace::self()->desktopList())
         c->finishCompositing();
         foreach (Unmanaged * c, Workspace::self()->unmanagedList())
         c->finishCompositing();
         foreach (Deleted * c, Workspace::self()->deletedList())
         c->finishCompositing();
         xcb_composite_unredirect_subwindows(connection(), rootWindow(), XCB_COMPOSITE_REDIRECT_MANUAL);
     }
     delete effects;
     effects = NULL;
     delete m_scene;
     m_scene = NULL;
     compositeTimer.stop();
     repaints_region = QRegion();
     if (Workspace::self()) {
         for (ClientList::ConstIterator it = Workspace::self()->clientList().constBegin();
                 it != Workspace::self()->clientList().constEnd();
                 ++it) {
             // forward all opacity values to the frame in case there'll be other CM running
             if ((*it)->opacity() != 1.0) {
                 NETWinInfo i(connection(), (*it)->frameId(), rootWindow(), 0, 0);
                 i.setOpacity(static_cast< unsigned long >((*it)->opacity() * 0xffffffff));
             }
         }
         // discard all Deleted windows (#152914)
         while (!Workspace::self()->deletedList().isEmpty())
             Workspace::self()->deletedList().first()->discard();
     }
     m_finishing = false;
     emit compositingToggled(false);
 }
 
 void Compositor::releaseCompositorSelection()
 {
     if (hasScene() && !m_finishing) {
         // compositor is up and running again, no need to release the selection
         return;
     }
     if (m_starting) {
         // currently still starting the compositor, it might fail, so restart the timer to test again
         m_releaseSelectionTimer.start();
         return;
     }
 
     if (m_finishing) {
         // still shutting down, a restart might follow, so restart the timer to test again
         m_releaseSelectionTimer.start();
         return;
     }
     qCDebug(KWIN_CORE) << "Releasing compositor selection";
     if (cm_selection) {
         cm_selection->owning = false;
         cm_selection->release();
     }
 }
 
 void Compositor::keepSupportProperty(xcb_atom_t atom)
 {
     m_unusedSupportProperties.removeAll(atom);
 }
 
 void Compositor::removeSupportProperty(xcb_atom_t atom)
 {
     m_unusedSupportProperties << atom;
     m_unusedSupportPropertyTimer.start();
 }
 
 void Compositor::deleteUnusedSupportProperties()
 {
     if (m_starting) {
         // currently still starting the compositor
         m_unusedSupportPropertyTimer.start();
         return;
     }
     if (m_finishing) {
         // still shutting down, a restart might follow
         m_unusedSupportPropertyTimer.start();
         return;
     }
     if (kwinApp()->x11Connection()) {
         foreach (const xcb_atom_t &atom, m_unusedSupportProperties) {
             // remove property from root window
             xcb_delete_property(connection(), rootWindow(), atom);
         }
     }
 }
 
 // OpenGL self-check failed, fallback to XRender
 void Compositor::fallbackToXRenderCompositing()
 {
     finish();
     KConfigGroup config(kwinApp()->config(), "Compositing");
     config.writeEntry("Backend", "XRender");
     config.sync();
     options->setCompositingMode(XRenderCompositing);
     setup();
 }
 
 void Compositor::slotConfigChanged()
 {
     if (!m_suspended) {
         setup();
         if (effects)   // setupCompositing() may fail
             effects->reconfigure();
         addRepaintFull();
     } else
         finish();
 }
 
 void Compositor::slotReinitialize()
 {
     // Reparse config. Config options will be reloaded by setup()
     kwinApp()->config()->reparseConfiguration();
 
     // Restart compositing
     finish();
     // resume compositing if suspended
     m_suspended = NoReasonSuspend;
     options->setCompositingInitialized(false);
     setup();
 
     if (effects) { // setup() may fail
         effects->reconfigure();
     }
 }
 
 // for the shortcut
 void Compositor::slotToggleCompositing()
 {
     if (kwinApp()->platform()->requiresCompositing()) {
         // we are not allowed to turn on/off compositing
         return;
     }
     if (m_suspended) { // direct user call; clear all bits
         resume(AllReasonSuspend);
     } else { // but only set the user one (sufficient to suspend)
         suspend(UserSuspend);
     }
 }
 
 void Compositor::updateCompositeBlocking()
 {
     updateCompositeBlocking(NULL);
 }
 
 void Compositor::updateCompositeBlocking(Client *c)
 {
     if (kwinApp()->platform()->requiresCompositing()) {
         return;
     }
     if (c) { // if c == 0 we just check if we can resume
         if (c->isBlockingCompositing()) {
             if (!(m_suspended & BlockRuleSuspend)) // do NOT attempt to call suspend(true); from within the eventchain!
                 QMetaObject::invokeMethod(this, "suspend", Qt::QueuedConnection, Q_ARG(Compositor::SuspendReason, BlockRuleSuspend));
         }
     }
     else if (m_suspended & BlockRuleSuspend) {  // lost a client and we're blocked - can we resume?
         bool resume = true;
         for (ClientList::ConstIterator it = Workspace::self()->clientList().constBegin(); it != Workspace::self()->clientList().constEnd(); ++it) {
             if ((*it)->isBlockingCompositing()) {
                 resume = false;
                 break;
             }
         }
         if (resume) { // do NOT attempt to call suspend(false); from within the eventchain!
             QMetaObject::invokeMethod(this, "resume", Qt::QueuedConnection, Q_ARG(Compositor::SuspendReason, BlockRuleSuspend));
         }
     }
 }
 
 void Compositor::suspend(Compositor::SuspendReason reason)
 {
     if (kwinApp()->platform()->requiresCompositing()) {
         return;
     }
     Q_ASSERT(reason != NoReasonSuspend);
     m_suspended |= reason;
     if (reason & KWin::Compositor::ScriptSuspend) {
         // when disabled show a shortcut how the user can get back compositing
         const auto shortcuts = KGlobalAccel::self()->shortcut(workspace()->findChild<QAction*>(QStringLiteral("Suspend Compositing")));
         if (!shortcuts.isEmpty()) {
             // display notification only if there is the shortcut
             const QString message = i18n("Desktop effects have been suspended by another application.<br/>"
                                          "You can resume using the '%1' shortcut.", shortcuts.first().toString(QKeySequence::NativeText));
             KNotification::event(QStringLiteral("compositingsuspendeddbus"), message);
         }
     }
     finish();
 }
 
 void Compositor::resume(Compositor::SuspendReason reason)
 {
     Q_ASSERT(reason != NoReasonSuspend);
     m_suspended &= ~reason;
     setup(); // signal "toggled" is eventually emitted from within setup
 }
 
 void Compositor::restart()
 {
     if (hasScene()) {
         finish();
         QTimer::singleShot(0, this, SLOT(setup()));
     }
 }
 
 void Compositor::addRepaint(int x, int y, int w, int h)
 {
     if (!hasScene())
         return;
     repaints_region += QRegion(x, y, w, h);
     scheduleRepaint();
 }
 
 void Compositor::addRepaint(const QRect& r)
 {
     if (!hasScene())
         return;
     repaints_region += r;
     scheduleRepaint();
 }
 
 void Compositor::addRepaint(const QRegion& r)
 {
     if (!hasScene())
         return;
     repaints_region += r;
     scheduleRepaint();
 }
 
 void Compositor::addRepaintFull()
 {
     if (!hasScene())
         return;
     const QSize &s = screens()->size();
     repaints_region = QRegion(0, 0, s.width(), s.height());
     scheduleRepaint();
 }
 
 void Compositor::timerEvent(QTimerEvent *te)
 {
     if (te->timerId() == compositeTimer.timerId()) {
         performCompositing();
     } else
         QObject::timerEvent(te);
 }
 
 void Compositor::aboutToSwapBuffers()
 {
     assert(!m_bufferSwapPending);
 
     m_bufferSwapPending = true;
 }
 
 void Compositor::bufferSwapComplete()
 {
     assert(m_bufferSwapPending);
     m_bufferSwapPending = false;
 
     if (m_composeAtSwapCompletion) {
         m_composeAtSwapCompletion = false;
         performCompositing();
     }
 }
 
 void Compositor::performCompositing()
 {
     if (m_scene->usesOverlayWindow() && !isOverlayWindowVisible())
         return; // nothing is visible anyway
 
     // If a buffer swap is still pending, we return to the event loop and
     // continue processing events until the swap has completed.
     if (m_bufferSwapPending) {
         m_composeAtSwapCompletion = true;
         compositeTimer.stop();
         return;
     }
 
     // If outputs are disabled, we return to the event loop and
     // continue processing events until the outputs are enabled again
     if (!kwinApp()->platform()->areOutputsEnabled()) {
         compositeTimer.stop();
         return;
     }
 
     // Create a list of all windows in the stacking order
     ToplevelList windows = Workspace::self()->xStackingOrder();
     ToplevelList damaged;
 
     // Reset the damage state of each window and fetch the damage region
     // without waiting for a reply
     foreach (Toplevel *win, windows) {
         if (win->resetAndFetchDamage())
             damaged << win;
     }
 
     if (damaged.count() > 0) {
         m_scene->triggerFence();
         xcb_flush(connection());
     }
 
     // Move elevated windows to the top of the stacking order
     foreach (EffectWindow *c, static_cast<EffectsHandlerImpl *>(effects)->elevatedWindows()) {
         Toplevel* t = static_cast< EffectWindowImpl* >(c)->window();
         windows.removeAll(t);
         windows.append(t);
     }
 
     // Get the replies
     foreach (Toplevel *win, damaged) {
         // Discard the cached lanczos texture
         if (win->effectWindow()) {
             const QVariant texture = win->effectWindow()->data(LanczosCacheRole);
             if (texture.isValid()) {
                 delete static_cast<GLTexture *>(texture.value<void*>());
                 win->effectWindow()->setData(LanczosCacheRole, QVariant());
             }
         }
 
         win->getDamageRegionReply();
     }
 
     if (repaints_region.isEmpty() && !windowRepaintsPending()) {
         m_scene->idle();
         m_timeSinceLastVBlank = fpsInterval - (options->vBlankTime() + 1); // means "start now"
         m_timeSinceStart += m_timeSinceLastVBlank;
         // Note: It would seem here we should undo suspended unredirect, but when scenes need
         // it for some reason, e.g. transformations or translucency, the next pass that does not
         // need this anymore and paints normally will also reset the suspended unredirect.
         // Otherwise the window would not be painted normally anyway.
         compositeTimer.stop();
         return;
     }
 
     // skip windows that are not yet ready for being painted and if screen is locked skip windows that are
     // neither lockscreen nor inputmethod windows
     // TODO ?
     // this cannot be used so carelessly - needs protections against broken clients, the window
     // should not get focus before it's displayed, handle unredirected windows properly and so on.
     foreach (Toplevel *t, windows) {
         if (!t->readyForPainting()) {
             windows.removeAll(t);
         }
         if (waylandServer() && waylandServer()->isScreenLocked()) {
             if(!t->isLockScreen() && !t->isInputMethod()) {
                 windows.removeAll(t);
             }
         }
     }
 
     QRegion repaints = repaints_region;
     // clear all repaints, so that post-pass can add repaints for the next repaint
     repaints_region = QRegion();
 
     m_timeSinceLastVBlank = m_scene->paint(repaints, windows);
     m_timeSinceStart += m_timeSinceLastVBlank;
 
     if (waylandServer()) {
         for (Toplevel *win : damaged) {
             if (auto surface = win->surface()) {
                 surface->frameRendered(m_timeSinceStart);
             }
         }
     }
 
     compositeTimer.stop(); // stop here to ensure *we* cause the next repaint schedule - not some effect through m_scene->paint()
 
     // Trigger at least one more pass even if there would be nothing to paint, so that scene->idle()
     // is called the next time. If there would be nothing pending, it will not restart the timer and
     // scheduleRepaint() would restart it again somewhen later, called from functions that
     // would again add something pending.
     if (m_bufferSwapPending && m_scene->syncsToVBlank()) {
         m_composeAtSwapCompletion = true;
     } else {
         scheduleRepaint();
     }
 }
 
 bool Compositor::windowRepaintsPending() const
 {
     foreach (Toplevel * c, Workspace::self()->clientList())
     if (!c->repaints().isEmpty())
         return true;
     foreach (Toplevel * c, Workspace::self()->desktopList())
     if (!c->repaints().isEmpty())
         return true;
     foreach (Toplevel * c, Workspace::self()->unmanagedList())
     if (!c->repaints().isEmpty())
         return true;
     foreach (Toplevel * c, Workspace::self()->deletedList())
     if (!c->repaints().isEmpty())
         return true;
     if (auto w = waylandServer()) {
         const auto &clients = w->clients();
         for (auto c : clients) {
             if (c->isShown(true) && !c->repaints().isEmpty()) {
                 return true;
             }
         }
         const auto &internalClients = w->internalClients();
         for (auto c : internalClients) {
             if (c->isShown(true) && !c->repaints().isEmpty()) {
                 return true;
             }
         }
     }
     return false;
 }
 
 void Compositor::setCompositeResetTimer(int msecs)
 {
     compositeResetTimer.start(msecs);
 }
 
 void Compositor::setCompositeTimer()
 {
     if (!hasScene())  // should not really happen, but there may be e.g. some damage events still pending
         return;
     if (m_starting || !Workspace::self()) {
         return;
     }
 
     // Don't start the timer if we're waiting for a swap event
     if (m_bufferSwapPending && m_composeAtSwapCompletion)
         return;
 
     // Don't start the timer if all outputs are disabled
     if (!kwinApp()->platform()->areOutputsEnabled()) {
         return;
     }
 
     uint waitTime = 1;
 
     if (m_scene->blocksForRetrace()) {
 
         // TODO: make vBlankTime dynamic?!
         // It's required because glXWaitVideoSync will *likely* block a full frame if one enters
         // a retrace pass which can last a variable amount of time, depending on the actual screen
         // Now, my ooold 19" CRT can do such retrace so that 2ms are entirely sufficient,
         // while another ooold 15" TFT requires about 6ms
 
         qint64 padding = m_timeSinceLastVBlank;
         if (padding > fpsInterval) {
             // we're at low repaints or spent more time in painting than the user wanted to wait for that frame
             padding = vBlankInterval - (padding%vBlankInterval); // -> align to next vblank
         } else {  // -> align to the next maxFps tick
             padding = ((vBlankInterval - padding%vBlankInterval) + (fpsInterval/vBlankInterval-1)*vBlankInterval);
             //               "remaining time of the first vsync" + "time for the other vsyncs of the frame"
         }
 
         if (padding < options->vBlankTime()) { // we'll likely miss this frame
             waitTime = nanoToMilli(padding + vBlankInterval - options->vBlankTime()); // so we add one
         } else {
             waitTime = nanoToMilli(padding - options->vBlankTime());
         }
     }
     else { // w/o blocking vsync we just jump to the next demanded tick
         if (fpsInterval > m_timeSinceLastVBlank) {
             waitTime = nanoToMilli(fpsInterval - m_timeSinceLastVBlank);
             if (!waitTime) {
                 waitTime = 1; // will ensure we don't block out the eventloop - the system's just not faster ...
             }
         }/* else if (m_scene->syncsToVBlank() && m_timeSinceLastVBlank - fpsInterval < (vBlankInterval<<1)) {
             // NOTICE - "for later" ------------------------------------------------------------------
             // It can happen that we push two frames within one refresh cycle.
             // Swapping will then block even with triple buffering when the GPU does not discard but
             // queues frames
             // now here's the mean part: if we take that as "OMG, we're late - next frame ASAP",
             // there'll immediately be 2 frames in the pipe, swapping will block, we think we're
             // late ... ewww
             // so instead we pad to the clock again and add 2ms safety to ensure the pipe is really
             // free
             // NOTICE: obviously m_timeSinceLastVBlank can be too big because we're too slow as well
             // So if this code was enabled, we'd needlessly half the framerate once more (15 instead of 30)
             waitTime = nanoToMilli(vBlankInterval - (m_timeSinceLastVBlank - fpsInterval)%vBlankInterval) + 2;
         }*/ else {
             waitTime = 1; // ... "0" would be sufficient, but the compositor isn't the WMs only task
         }
     }
     compositeTimer.start(qMin(waitTime, 250u), this); // force 4fps minimum
 }
 
 bool Compositor::isActive()
 {
     return !m_finishing && hasScene();
 }
 
 void Compositor::checkUnredirect()
 {
     checkUnredirect(false);
 }
 
 // force is needed when the list of windows changes (e.g. a window goes away)
 void Compositor::checkUnredirect(bool force)
 {
     if (!hasScene() || !m_scene->overlayWindow() || m_scene->overlayWindow()->window() == None || !options->isUnredirectFullscreen())
         return;
     if (force)
         forceUnredirectCheck = true;
     if (!unredirectTimer.isActive())
         unredirectTimer.start(0);
 }
 
 void Compositor::delayedCheckUnredirect()
 {
     if (!hasScene() || !m_scene->overlayWindow() || m_scene->overlayWindow()->window() == None || !(options->isUnredirectFullscreen() || sender() == options))
         return;
     ToplevelList list;
     bool changed = forceUnredirectCheck;
     foreach (Client * c, Workspace::self()->clientList())
         list.append(c);
     foreach (Unmanaged * c, Workspace::self()->unmanagedList())
         list.append(c);
     foreach (Toplevel * c, list) {
         if (c->updateUnredirectedState()) {
             changed = true;
             break;
         }
     }
     // no desktops, no Deleted ones
     if (!changed)
         return;
     forceUnredirectCheck = false;
     // Cut out parts from the overlay window where unredirected windows are,
     // so that they are actually visible.
     const QSize &s = screens()->size();
     QRegion reg(0, 0, s.width(), s.height());
     foreach (Toplevel * c, list) {
         if (c->unredirected())
             reg -= c->geometry();
     }
     m_scene->overlayWindow()->setShape(reg);
     addRepaint(reg);
 }
 
 bool Compositor::checkForOverlayWindow(WId w) const
 {
     if (!hasScene()) {
         // no scene, so it cannot be the overlay window
         return false;
     }
     if (!m_scene->overlayWindow()) {
         // no overlay window, it cannot be the overlay
         return false;
     }
     // and compare the window ID's
     return w == m_scene->overlayWindow()->window();
 }
 
 WId Compositor::overlayWindow() const
 {
     if (!hasScene()) {
         return None;
     }
     if (!m_scene->overlayWindow()) {
         return None;
     }
     return m_scene->overlayWindow()->window();
 }
 
 bool Compositor::isOverlayWindowVisible() const
 {
     if (!hasScene()) {
         return false;
     }
     if (!m_scene->overlayWindow()) {
         return false;
     }
     return m_scene->overlayWindow()->isVisible();
 }
 
 void Compositor::setOverlayWindowVisibility(bool visible)
 {
     if (hasScene() && m_scene->overlayWindow()) {
         m_scene->overlayWindow()->setVisibility(visible);
     }
 }
 
 /*****************************************************
  * Workspace
  ****************************************************/
 
 bool Workspace::compositing() const
 {
     return m_compositor && m_compositor->hasScene();
 }
 
 //****************************************
 // Toplevel
 //****************************************
 
 bool Toplevel::setupCompositing()
 {
     if (!compositing())
         return false;
 
     if (damage_handle != XCB_NONE)
         return false;
 
     if (kwinApp()->operationMode() == Application::OperationModeX11 && !surface()) {
         damage_handle = xcb_generate_id(connection());
         xcb_damage_create(connection(), damage_handle, frameId(), XCB_DAMAGE_REPORT_LEVEL_NON_EMPTY);
     }
 
     damage_region = QRegion(0, 0, width(), height());
     effect_window = new EffectWindowImpl(this);
     unredirect = false;
 
     Compositor::self()->checkUnredirect(true);
     Compositor::self()->scene()->windowAdded(this);
 
     // With unmanaged windows there is a race condition between the client painting the window
     // and us setting up damage tracking.  If the client wins we won't get a damage event even
     // though the window has been painted.  To avoid this we mark the whole window as damaged
     // and schedule a repaint immediately after creating the damage object.
     if (dynamic_cast<Unmanaged*>(this))
         addDamageFull();
 
     return true;
 }
 
 void Toplevel::finishCompositing(ReleaseReason releaseReason)
 {
     if (kwinApp()->operationMode() == Application::OperationModeX11 && damage_handle == XCB_NONE)
         return;
     Compositor::self()->checkUnredirect(true);
     if (effect_window->window() == this) { // otherwise it's already passed to Deleted, don't free data
         discardWindowPixmap();
         delete effect_window;
     }
 
     if (damage_handle != XCB_NONE &&
             releaseReason != ReleaseReason::Destroyed) {
         xcb_damage_destroy(connection(), damage_handle);
     }
 
     damage_handle = XCB_NONE;
     damage_region = QRegion();
     repaints_region = QRegion();
     effect_window = NULL;
 }
 
 void Toplevel::discardWindowPixmap()
 {
     addDamageFull();
     if (effectWindow() != NULL && effectWindow()->sceneWindow() != NULL)
         effectWindow()->sceneWindow()->pixmapDiscarded();
 }
 
 void Toplevel::damageNotifyEvent()
 {
     m_isDamaged = true;
 
     // Note: The rect is supposed to specify the damage extents,
     //       but we don't know it at this point. No one who connects
     //       to this signal uses the rect however.
     emit damaged(this, QRect());
 }
 
 bool Toplevel::compositing() const
 {
     return Workspace::self()->compositing();
 }
 
 void Client::damageNotifyEvent()
 {
     if (syncRequest.isPending && isResize()) {
         emit damaged(this, QRect());
         m_isDamaged = true;
         return;
     }
 
     if (!ready_for_painting) { // avoid "setReadyForPainting()" function calling overhead
         if (syncRequest.counter == XCB_NONE) {  // cannot detect complete redraw, consider done now
             setReadyForPainting();
             setupWindowManagementInterface();
         }
     }
 
     Toplevel::damageNotifyEvent();
 }
 
 bool Toplevel::resetAndFetchDamage()
 {
     if (!m_isDamaged)
         return false;
 
     if (damage_handle == XCB_NONE) {
         m_isDamaged = false;
         return true;
     }
 
     xcb_connection_t *conn = connection();
 
     // Create a new region and copy the damage region to it,
     // resetting the damaged state.
     xcb_xfixes_region_t region = xcb_generate_id(conn);
     xcb_xfixes_create_region(conn, region, 0, 0);
     xcb_damage_subtract(conn, damage_handle, 0, region);
 
     // Send a fetch-region request and destroy the region
     m_regionCookie = xcb_xfixes_fetch_region_unchecked(conn, region);
     xcb_xfixes_destroy_region(conn, region);
 
     m_isDamaged = false;
     m_damageReplyPending = true;
 
     return m_damageReplyPending;
 }
 
 void Toplevel::getDamageRegionReply()
 {
     if (!m_damageReplyPending)
         return;
 
     m_damageReplyPending = false;
 
     // Get the fetch-region reply
     xcb_xfixes_fetch_region_reply_t *reply =
             xcb_xfixes_fetch_region_reply(connection(), m_regionCookie, 0);
 
     if (!reply)
         return;
 
     // Convert the reply to a QRegion
     int count = xcb_xfixes_fetch_region_rectangles_length(reply);
     QRegion region;
 
     if (count > 1 && count < 16) {
         xcb_rectangle_t *rects = xcb_xfixes_fetch_region_rectangles(reply);
 
         QVector<QRect> qrects;
         qrects.reserve(count);
 
         for (int i = 0; i < count; i++)
             qrects << QRect(rects[i].x, rects[i].y, rects[i].width, rects[i].height);
 
         region.setRects(qrects.constData(), count);
     } else
         region += QRect(reply->extents.x, reply->extents.y,
                         reply->extents.width, reply->extents.height);
 
     damage_region += region;
     repaints_region += region;
 
     free(reply);
 }
 
 void Toplevel::addDamageFull()
 {
     if (!compositing())
         return;
 
     damage_region = rect();
     repaints_region |= rect();
 
     emit damaged(this, rect());
 }
 
 void Toplevel::resetDamage()
 {
     damage_region = QRegion();
 }
 
 void Toplevel::addRepaint(const QRect& r)
 {
     if (!compositing()) {
         return;
     }
     repaints_region += r;
     emit needsRepaint();
 }
 
 void Toplevel::addRepaint(int x, int y, int w, int h)
 {
     QRect r(x, y, w, h);
     addRepaint(r);
 }
 
 void Toplevel::addRepaint(const QRegion& r)
 {
     if (!compositing()) {
         return;
     }
     repaints_region += r;
     emit needsRepaint();
 }
 
 void Toplevel::addLayerRepaint(const QRect& r)
 {
     if (!compositing()) {
         return;
     }
     layer_repaints_region += r;
     emit needsRepaint();
 }
 
 void Toplevel::addLayerRepaint(int x, int y, int w, int h)
 {
     QRect r(x, y, w, h);
     addLayerRepaint(r);
 }
 
 void Toplevel::addLayerRepaint(const QRegion& r)
 {
     if (!compositing())
         return;
     layer_repaints_region += r;
     emit needsRepaint();
 }
 
 void Toplevel::addRepaintFull()
 {
     repaints_region = visibleRect().translated(-pos());
     emit needsRepaint();
 }
 
 void Toplevel::resetRepaints()
 {
     repaints_region = QRegion();
     layer_repaints_region = QRegion();
 }
 
 void Toplevel::addWorkspaceRepaint(int x, int y, int w, int h)
 {
     addWorkspaceRepaint(QRect(x, y, w, h));
 }
 
 void Toplevel::addWorkspaceRepaint(const QRect& r2)
 {
     if (!compositing())
         return;
     Compositor::self()->addRepaint(r2);
 }
 
 bool Toplevel::updateUnredirectedState()
 {
     assert(compositing());
     bool should = options->isUnredirectFullscreen() && shouldUnredirect() && !unredirectSuspend &&
                   !shape() && !hasAlpha() && opacity() == 1.0 &&
                   !static_cast<EffectsHandlerImpl*>(effects)->activeFullScreenEffect();
     if (should == unredirect)
         return false;
     static QElapsedTimer lastUnredirect;
     static const qint64 msecRedirectInterval = 100;
     if (!lastUnredirect.hasExpired(msecRedirectInterval)) {
         QTimer::singleShot(msecRedirectInterval, Compositor::self(), SLOT(checkUnredirect()));
         return false;
     }
     lastUnredirect.start();
     unredirect = should;
     if (unredirect) {
         qCDebug(KWIN_CORE) << "Unredirecting:" << this;
         xcb_composite_unredirect_window(connection(), frameId(), XCB_COMPOSITE_REDIRECT_MANUAL);
     } else {
         qCDebug(KWIN_CORE) << "Redirecting:" << this;
         xcb_composite_redirect_window(connection(), frameId(), XCB_COMPOSITE_REDIRECT_MANUAL);
         discardWindowPixmap();
     }
     return true;
 }
 
 void Toplevel::suspendUnredirect(bool suspend)
 {
     if (unredirectSuspend == suspend)
         return;
     unredirectSuspend = suspend;
     Compositor::self()->checkUnredirect();
 }
 
 //****************************************
 // Client
 //****************************************
 
 bool Client::setupCompositing()
 {
     if (!Toplevel::setupCompositing()){
         return false;
     }
     if (isDecorated()) {
         decoratedClient()->destroyRenderer();
     }
     updateVisibility(); // for internalKeep()
     return true;
 }
 
 void Client::finishCompositing(ReleaseReason releaseReason)
 {
     Toplevel::finishCompositing(releaseReason);
     updateVisibility();
     if (!deleting) {
         if (isDecorated()) {
             decoratedClient()->destroyRenderer();
         }
     }
     // for safety in case KWin is just resizing the window
     resetHaveResizeEffect();
 }
 
 bool Client::shouldUnredirect() const
 {
     if (isActiveFullScreen()) {
         ToplevelList stacking = workspace()->xStackingOrder();
         for (int pos = stacking.count() - 1;
                 pos >= 0;
                 --pos) {
             Toplevel* c = stacking.at(pos);
             if (c == this)   // is not covered by any other window, ok to unredirect
                 return true;
             if (c->geometry().intersects(geometry()))
                 return false;
         }
         abort();
     }
     return false;
 }
 
 
 //****************************************
 // Unmanaged
 //****************************************
 
 bool Unmanaged::shouldUnredirect() const
 {
     // the pixmap is needed for the login effect, a nicer solution would be the login effect increasing
     // refcount for the window pixmap (which would prevent unredirect), avoiding this hack
     if (resourceClass() == "ksplashx"
             || resourceClass() == "ksplashsimple"
             || resourceClass() == "ksplashqml"
             )
         return false;
 // it must cover whole display or one xinerama screen, and be the topmost there
     const int desktop = VirtualDesktopManager::self()->current();
     if (geometry() == workspace()->clientArea(FullArea, geometry().center(), desktop)
             || geometry() == workspace()->clientArea(ScreenArea, geometry().center(), desktop)) {
         ToplevelList stacking = workspace()->xStackingOrder();
         for (int pos = stacking.count() - 1;
                 pos >= 0;
                 --pos) {
             Toplevel* c = stacking.at(pos);
             if (c == this)   // is not covered by any other window, ok to unredirect
                 return true;
             if (c->geometry().intersects(geometry()))
                 return false;
         }
         abort();
     }
     return false;
 }
 
 //****************************************
 // Deleted
 //****************************************
 
 bool Deleted::shouldUnredirect() const
 {
     return false;
 }
 
 
 } // namespace
diff --git a/compositingprefs.cpp b/compositingprefs.cpp
deleted file mode 100644
index ab7d16fc1..000000000
--- a/compositingprefs.cpp
+++ /dev/null
@@ -1,129 +0,0 @@
-/********************************************************************
- KWin - the KDE window manager
- This file is part of the KDE project.
-
-Copyright (C) 2007 Rivo Laks <rivolaks@hot.ee>
-
-This program is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*********************************************************************/
-
-#include "compositingprefs.h"
-
-#include "main.h"
-#include "xcbutils.h"
-#include "kwinglplatform.h"
-#include "utils.h"
-
-#include <kconfiggroup.h>
-#include <KLocalizedString>
-#include <ksharedconfig.h>
-
-#include <QDebug>
-#include <QOpenGLContext>
-#include <QStandardPaths>
-#include <qprocess.h>
-
-
-namespace KWin
-{
-
-extern int screen_number; // main.cpp
-extern bool is_multihead;
-
-CompositingPrefs::CompositingPrefs()
-{
-}
-
-CompositingPrefs::~CompositingPrefs()
-{
-}
-
-bool CompositingPrefs::openGlIsBroken()
-{
-    const QString unsafeKey(QLatin1String("OpenGLIsUnsafe") + (is_multihead ? QString::number(screen_number) : QString()));
-    return KConfigGroup(kwinApp()->config(), "Compositing").readEntry(unsafeKey, false);
-}
-
-bool CompositingPrefs::compositingPossible()
-{
-    // first off, check whether we figured that we'll crash on detection because of a buggy driver
-    KConfigGroup gl_workaround_group(kwinApp()->config(), "Compositing");
-    const QString unsafeKey(QLatin1String("OpenGLIsUnsafe") + (is_multihead ? QString::number(screen_number) : QString()));
-    if (gl_workaround_group.readEntry("Backend", "OpenGL") == QLatin1String("OpenGL") &&
-        gl_workaround_group.readEntry(unsafeKey, false))
-        return false;
-
-    if (kwinApp()->shouldUseWaylandForCompositing()) {
-        // don't do X specific checks if we are not going to use X for compositing
-        return true;
-    }
-
-    if (!Xcb::Extensions::self()->isCompositeAvailable()) {
-        qCDebug(KWIN_CORE) << "No composite extension available";
-        return false;
-    }
-    if (!Xcb::Extensions::self()->isDamageAvailable()) {
-        qCDebug(KWIN_CORE) << "No damage extension available";
-        return false;
-    }
-    if (hasGlx())
-        return true;
-#ifdef KWIN_HAVE_XRENDER_COMPOSITING
-    if (Xcb::Extensions::self()->isRenderAvailable() && Xcb::Extensions::self()->isFixesAvailable())
-        return true;
-#endif
-    if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGLES) {
-        return true;
-    } else if (qstrcmp(qgetenv("KWIN_COMPOSE"), "O2ES") == 0) {
-        return true;
-    }
-    qCDebug(KWIN_CORE) << "No OpenGL or XRender/XFixes support";
-    return false;
-}
-
-QString CompositingPrefs::compositingNotPossibleReason()
-{
-    // first off, check whether we figured that we'll crash on detection because of a buggy driver
-    KConfigGroup gl_workaround_group(kwinApp()->config(), "Compositing");
-    const QString unsafeKey(QLatin1String("OpenGLIsUnsafe") + (is_multihead ? QString::number(screen_number) : QString()));
-    if (gl_workaround_group.readEntry("Backend", "OpenGL") == QLatin1String("OpenGL") &&
-        gl_workaround_group.readEntry(unsafeKey, false))
-        return i18n("<b>OpenGL compositing (the default) has crashed KWin in the past.</b><br>"
-                    "This was most likely due to a driver bug."
-                    "<p>If you think that you have meanwhile upgraded to a stable driver,<br>"
-                    "you can reset this protection but <b>be aware that this might result in an immediate crash!</b></p>"
-                    "<p>Alternatively, you might want to use the XRender backend instead.</p>");
-
-    if (!Xcb::Extensions::self()->isCompositeAvailable() || !Xcb::Extensions::self()->isDamageAvailable()) {
-        return i18n("Required X extensions (XComposite and XDamage) are not available.");
-    }
-#if !defined( KWIN_HAVE_XRENDER_COMPOSITING )
-    if (!hasGlx())
-        return i18n("GLX/OpenGL are not available and only OpenGL support is compiled.");
-#else
-    if (!(hasGlx()
-            || (Xcb::Extensions::self()->isRenderAvailable() && Xcb::Extensions::self()->isFixesAvailable()))) {
-        return i18n("GLX/OpenGL and XRender/XFixes are not available.");
-    }
-#endif
-    return QString();
-}
-
-bool CompositingPrefs::hasGlx()
-{
-    return Xcb::Extensions::self()->hasGlx();
-}
-
-} // namespace
-
diff --git a/compositingprefs.h b/compositingprefs.h
deleted file mode 100644
index 889ed8b97..000000000
--- a/compositingprefs.h
+++ /dev/null
@@ -1,59 +0,0 @@
-/********************************************************************
- KWin - the KDE window manager
- This file is part of the KDE project.
-
-Copyright (C) 2007 Rivo Laks <rivolaks@hot.ee>
-
-This program is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*********************************************************************/
-
-#ifndef KWIN_COMPOSITINGPREFS_H
-#define KWIN_COMPOSITINGPREFS_H
-
-#include <QString>
-#include <QStringList>
-
-#include "kwinglutils.h"
-#include "kwinglobals.h"
-
-
-namespace KWin
-{
-
-class CompositingPrefs
-{
-public:
-    CompositingPrefs();
-    ~CompositingPrefs();
-
-    static bool compositingPossible();
-    static QString compositingNotPossibleReason();
-    static bool openGlIsBroken();
-    /**
-     * Tests whether GLX is supported and returns @c true
-     * in case KWin is compiled with OpenGL support and GLX
-     * is available.
-     *
-     * If KWin is compiled with OpenGL ES or without OpenGL at
-     * all, @c false is returned.
-     * @returns @c true if GLX is available, @c false otherwise and if not build with OpenGL support.
-     **/
-    static bool hasGlx();
-};
-
-}
-
-#endif //KWIN_COMPOSITINGPREFS_H
-
-
diff --git a/dbusinterface.cpp b/dbusinterface.cpp
index 99dd7762b..302355bd9 100644
--- a/dbusinterface.cpp
+++ b/dbusinterface.cpp
@@ -1,265 +1,265 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2012 Martin Gräßlin <mgraesslin@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 
 // own
 #include "dbusinterface.h"
 #include "compositingadaptor.h"
 
 // kwin
 #include "atoms.h"
 #include "composite.h"
-#include "compositingprefs.h"
 #include "debug_console.h"
 #include "main.h"
 #include "placement.h"
+#include "platform.h"
 #include "kwinadaptor.h"
 #include "scene.h"
 #include "workspace.h"
 #include "virtualdesktops.h"
 #ifdef KWIN_BUILD_ACTIVITIES
 #include "activities.h"
 #endif
 
 // Qt
 #include <QOpenGLContext>
 #include <QDBusServiceWatcher>
 
 namespace KWin
 {
 
 DBusInterface::DBusInterface(QObject *parent)
     : QObject(parent)
     , m_serviceName(QStringLiteral("org.kde.KWin"))
 {
     (void) new KWinAdaptor(this);
 
     QDBusConnection dbus = QDBusConnection::sessionBus();
     dbus.registerObject(QStringLiteral("/KWin"), this);
     const QByteArray dBusSuffix = qgetenv("KWIN_DBUS_SERVICE_SUFFIX");
     if (!dBusSuffix.isNull()) {
         m_serviceName = m_serviceName + QLatin1Char('.') + dBusSuffix;
     }
     if (!dbus.registerService(m_serviceName)) {
         QDBusServiceWatcher *dog = new QDBusServiceWatcher(m_serviceName, dbus, QDBusServiceWatcher::WatchForUnregistration, this);
         connect (dog, SIGNAL(serviceUnregistered(QString)), SLOT(becomeKWinService(QString)));
     } else {
         announceService();
     }
     dbus.connect(QString(), QStringLiteral("/KWin"), QStringLiteral("org.kde.KWin"), QStringLiteral("reloadConfig"),
                  Workspace::self(), SLOT(slotReloadConfig()));
 }
 
 void DBusInterface::becomeKWinService(const QString &service)
 {
     // TODO: this watchdog exists to make really safe that we at some point get the service
     // but it's probably no longer needed since we explicitly unregister the service with the deconstructor
     if (service == m_serviceName && QDBusConnection::sessionBus().registerService(m_serviceName) && sender()) {
         sender()->deleteLater(); // bye doggy :'(
         announceService();
     }
 }
 
 DBusInterface::~DBusInterface()
 {
     QDBusConnection::sessionBus().unregisterService(m_serviceName);
     // KApplication automatically also grabs org.kde.kwin, so it's often been used externally - ensure to free it as well
     QDBusConnection::sessionBus().unregisterService(QStringLiteral("org.kde.kwin"));
     xcb_delete_property(connection(), rootWindow(), atoms->kwin_dbus_service);
 }
 
 void DBusInterface::announceService()
 {
     const QByteArray service = m_serviceName.toUtf8();
     xcb_change_property(connection(), XCB_PROP_MODE_REPLACE, rootWindow(), atoms->kwin_dbus_service,
                         atoms->utf8_string, 8, service.size(), service.constData());
 }
 
 // wrap void methods with no arguments to Workspace
 #define WRAP(name) \
 void DBusInterface::name() \
 {\
     Workspace::self()->name();\
 }
 
 WRAP(reconfigure)
 
 #undef WRAP
 
 void DBusInterface::killWindow()
 {
     Workspace::self()->slotKillWindow();
 }
 
 #define WRAP(name) \
 void DBusInterface::name() \
 {\
     Placement::self()->name();\
 }
 
 WRAP(cascadeDesktop)
 WRAP(unclutterDesktop)
 
 #undef WRAP
 
 // wrap returning methods with no arguments to Workspace
 #define WRAP( rettype, name ) \
 rettype DBusInterface::name( ) \
 {\
     return Workspace::self()->name(); \
 }
 
 WRAP(QString, supportInformation)
 
 #undef WRAP
 
 bool DBusInterface::startActivity(const QString &in0)
 {
 #ifdef KWIN_BUILD_ACTIVITIES
     if (!Activities::self()) {
         return false;
     }
     return Activities::self()->start(in0);
 #else
     Q_UNUSED(in0)
     return false;
 #endif
 }
 
 bool DBusInterface::stopActivity(const QString &in0)
 {
 #ifdef KWIN_BUILD_ACTIVITIES
     if (!Activities::self()) {
         return false;
     }
     return Activities::self()->stop(in0);
 #else
     Q_UNUSED(in0)
     return false;
 #endif
 }
 
 int DBusInterface::currentDesktop()
 {
     return VirtualDesktopManager::self()->current();
 }
 
 bool DBusInterface::setCurrentDesktop(int desktop)
 {
     return VirtualDesktopManager::self()->setCurrent(desktop);
 }
 
 void DBusInterface::nextDesktop()
 {
     VirtualDesktopManager::self()->moveTo<DesktopNext>();
 }
 
 void DBusInterface::previousDesktop()
 {
     VirtualDesktopManager::self()->moveTo<DesktopPrevious>();
 }
 
 void DBusInterface::showDebugConsole()
 {
     DebugConsole *console = new DebugConsole;
     console->show();
 }
 
 CompositorDBusInterface::CompositorDBusInterface(Compositor *parent)
     : QObject(parent)
     , m_compositor(parent)
 {
     connect(m_compositor, &Compositor::compositingToggled, this, &CompositorDBusInterface::compositingToggled);
     new CompositingAdaptor(this);
     QDBusConnection dbus = QDBusConnection::sessionBus();
     dbus.registerObject(QStringLiteral("/Compositor"), this);
     dbus.connect(QString(), QStringLiteral("/Compositor"), QStringLiteral("org.kde.kwin.Compositing"),
                  QStringLiteral("reinit"), m_compositor, SLOT(slotReinitialize()));
 }
 
 QString CompositorDBusInterface::compositingNotPossibleReason() const
 {
-    return CompositingPrefs::compositingNotPossibleReason();
+    return kwinApp()->platform()->compositingNotPossibleReason();
 }
 
 QString CompositorDBusInterface::compositingType() const
 {
     if (!m_compositor->hasScene()) {
         return QStringLiteral("none");
     }
     switch (m_compositor->scene()->compositingType()) {
     case XRenderCompositing:
         return QStringLiteral("xrender");
     case OpenGL2Compositing:
         if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGLES) {
             return QStringLiteral("gles");
         } else {
             return QStringLiteral("gl2");
         }
     case QPainterCompositing:
         return QStringLiteral("qpainter");
     case NoCompositing:
     default:
         return QStringLiteral("none");
     }
 }
 
 bool CompositorDBusInterface::isActive() const
 {
     return m_compositor->isActive();
 }
 
 bool CompositorDBusInterface::isCompositingPossible() const
 {
-    return CompositingPrefs::compositingPossible();
+    return kwinApp()->platform()->compositingPossible();
 }
 
 bool CompositorDBusInterface::isOpenGLBroken() const
 {
-    return CompositingPrefs::openGlIsBroken();
+    return kwinApp()->platform()->openGLCompositingIsBroken();
 }
 
 void CompositorDBusInterface::resume()
 {
     m_compositor->resume(Compositor::ScriptSuspend);
 }
 
 void CompositorDBusInterface::suspend()
 {
     m_compositor->suspend(Compositor::ScriptSuspend);
 }
 
 QStringList CompositorDBusInterface::supportedOpenGLPlatformInterfaces() const
 {
     QStringList interfaces;
     bool supportsGlx = false;
 #if HAVE_EPOXY_GLX
     supportsGlx = (kwinApp()->operationMode() == Application::OperationModeX11);
 #endif
     if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGLES) {
         supportsGlx = false;
     }
     if (supportsGlx) {
         interfaces << QStringLiteral("glx");
     }
     interfaces << QStringLiteral("egl");
     return interfaces;
 }
 
 } // namespace
diff --git a/options.cpp b/options.cpp
index 9054cffde..dbd957fed 100644
--- a/options.cpp
+++ b/options.cpp
@@ -1,1172 +1,1171 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 1999, 2000 Matthias Ettrich <ettrich@kde.org>
 Copyright (C) 2003 Lubos Lunak <l.lunak@kde.org>
 Copyright (C) 2012 Martin Gräßlin <m.graesslin@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 
 #include "options.h"
 #include "config-kwin.h"
 #include "utils.h"
 #include "platform.h"
 
 #ifndef KCMRULES
 
 #include <QProcess>
 
-#include "compositingprefs.h"
 #include "screens.h"
 #include "settings.h"
 #include "xcbutils.h"
 #include <kwinglplatform.h>
 #include <QOpenGLContext>
 
 #endif //KCMRULES
 
 namespace KWin
 {
 
 #ifndef KCMRULES
 
 int currentRefreshRate()
 {
     int rate = -1;
     QString syncScreenName(QLatin1String("primary screen"));
     if (options->refreshRate() > 0) {  // use manually configured refresh rate
         rate = options->refreshRate();
     } else if (Screens::self()->count() > 0) {
         // prefer the refreshrate calculated from the screens mode information
         // at least the nvidia driver reports 50Hz BS ... *again*!
         int syncScreen = 0;
         if (Screens::self()->count() > 1) {
             const QByteArray syncDisplayDevice(qgetenv("__GL_SYNC_DISPLAY_DEVICE"));
             // if __GL_SYNC_DISPLAY_DEVICE is exported, the GPU shall sync to that device
             // so we try to use its refresh rate
             if (!syncDisplayDevice.isEmpty()) {
                 for (int i = 0; i < Screens::self()->count(); ++i) {
                     if (Screens::self()->name(i) == syncDisplayDevice) {
                         syncScreenName = Screens::self()->name(i);
                         syncScreen = i;
                         break;
                     }
                 }
             }
         }
         rate = qRound(Screens::self()->refreshRate(syncScreen)); // TODO forward float precision?
     } else if (Xcb::Extensions::self()->isRandrAvailable()) {
         // last restort - query XRandR screenInfo rate - probably wrong on nvidia systems
         Xcb::RandR::ScreenInfo screenInfo(rootWindow());
         rate = screenInfo->rate;
     }
 
     // 0Hz or less is invalid, so we fallback to a default rate
     if (rate <= 0)
         rate = 60; // and not shitty 50Hz for sure! *grrr*
 
     // QTimer gives us 1msec (1000Hz) at best, so we ignore anything higher;
     // however, additional throttling prevents very high rates from taking place anyway
     else if (rate > 1000)
         rate = 1000;
     qCDebug(KWIN_CORE) << "Vertical Refresh rate " << rate << "Hz (" << syncScreenName << ")";
     return rate;
 }
 
 Options::Options(QObject *parent)
     : QObject(parent)
     , m_settings(new Settings(kwinApp()->config()))
     , m_focusPolicy(ClickToFocus)
     , m_nextFocusPrefersMouse(false)
     , m_clickRaise(false)
     , m_autoRaise(false)
     , m_autoRaiseInterval(0)
     , m_delayFocusInterval(0)
     , m_shadeHover(false)
     , m_shadeHoverInterval(0)
     , m_separateScreenFocus(false)
     , m_placement(Placement::NoPlacement)
     , m_borderSnapZone(0)
     , m_windowSnapZone(0)
     , m_centerSnapZone(0)
     , m_snapOnlyWhenOverlapping(false)
     , m_rollOverDesktops(false)
     , m_focusStealingPreventionLevel(0)
     , m_legacyFullscreenSupport(false)
     , m_killPingTimeout(0)
     , m_hideUtilityWindowsForInactive(false)
     , m_inactiveTabsSkipTaskbar(false)
     , m_autogroupSimilarWindows(false)
     , m_autogroupInForeground(false)
     , m_compositingMode(Options::defaultCompositingMode())
     , m_useCompositing(Options::defaultUseCompositing())
     , m_compositingInitialized(Options::defaultCompositingInitialized())
     , m_hiddenPreviews(Options::defaultHiddenPreviews())
     , m_unredirectFullscreen(Options::defaultUnredirectFullscreen())
     , m_glSmoothScale(Options::defaultGlSmoothScale())
     , m_colorCorrected(Options::defaultColorCorrected())
     , m_xrenderSmoothScale(Options::defaultXrenderSmoothScale())
     , m_maxFpsInterval(Options::defaultMaxFpsInterval())
     , m_refreshRate(Options::defaultRefreshRate())
     , m_vBlankTime(Options::defaultVBlankTime())
     , m_glStrictBinding(Options::defaultGlStrictBinding())
     , m_glStrictBindingFollowsDriver(Options::defaultGlStrictBindingFollowsDriver())
     , m_glCoreProfile(Options::defaultGLCoreProfile())
     , m_glPreferBufferSwap(Options::defaultGlPreferBufferSwap())
     , m_glPlatformInterface(Options::defaultGlPlatformInterface())
     , OpTitlebarDblClick(Options::defaultOperationTitlebarDblClick())
     , CmdActiveTitlebar1(Options::defaultCommandActiveTitlebar1())
     , CmdActiveTitlebar2(Options::defaultCommandActiveTitlebar2())
     , CmdActiveTitlebar3(Options::defaultCommandActiveTitlebar3())
     , CmdInactiveTitlebar1(Options::defaultCommandInactiveTitlebar1())
     , CmdInactiveTitlebar2(Options::defaultCommandInactiveTitlebar2())
     , CmdInactiveTitlebar3(Options::defaultCommandInactiveTitlebar3())
     , CmdTitlebarWheel(Options::defaultCommandTitlebarWheel())
     , CmdWindow1(Options::defaultCommandWindow1())
     , CmdWindow2(Options::defaultCommandWindow2())
     , CmdWindow3(Options::defaultCommandWindow3())
     , CmdWindowWheel(Options::defaultCommandWindowWheel())
     , CmdAll1(Options::defaultCommandAll1())
     , CmdAll2(Options::defaultCommandAll2())
     , CmdAll3(Options::defaultCommandAll3())
     , CmdAllWheel(Options::defaultCommandAllWheel())
     , CmdAllModKey(Options::defaultKeyCmdAllModKey())
     , electric_border_maximize(false)
     , electric_border_tiling(false)
     , electric_border_corner_ratio(0.0)
     , borderless_maximized_windows(false)
     , show_geometry_tip(false)
     , condensed_title(false)
     , animationSpeed(Options::defaultAnimationSpeed())
 {
     m_settings->setDefaults();
     syncFromKcfgc();
 }
 
 Options::~Options()
 {
 }
 
 void Options::setFocusPolicy(FocusPolicy focusPolicy)
 {
     if (m_focusPolicy == focusPolicy) {
         return;
     }
     m_focusPolicy = focusPolicy;
     emit focusPolicyChanged();
     if (m_focusPolicy == ClickToFocus) {
         setAutoRaise(false);
         setAutoRaiseInterval(0);
         setDelayFocusInterval(0);
     }
 }
 
 void Options::setNextFocusPrefersMouse(bool nextFocusPrefersMouse)
 {
     if (m_nextFocusPrefersMouse == nextFocusPrefersMouse) {
         return;
     }
     m_nextFocusPrefersMouse = nextFocusPrefersMouse;
     emit nextFocusPrefersMouseChanged();
 }
 
 void Options::setClickRaise(bool clickRaise)
 {
     if (m_autoRaise) {
         // important: autoRaise implies ClickRaise
         clickRaise = true;
     }
     if (m_clickRaise == clickRaise) {
         return;
     }
     m_clickRaise = clickRaise;
     emit clickRaiseChanged();
 }
 
 void Options::setAutoRaise(bool autoRaise)
 {
     if (m_focusPolicy == ClickToFocus) {
         autoRaise = false;
     }
     if (m_autoRaise == autoRaise) {
         return;
     }
     m_autoRaise = autoRaise;
     if (m_autoRaise) {
         // important: autoRaise implies ClickRaise
         setClickRaise(true);
     }
     emit autoRaiseChanged();
 }
 
 void Options::setAutoRaiseInterval(int autoRaiseInterval)
 {
     if (m_focusPolicy == ClickToFocus) {
         autoRaiseInterval = 0;
     }
     if (m_autoRaiseInterval == autoRaiseInterval) {
         return;
     }
     m_autoRaiseInterval = autoRaiseInterval;
     emit autoRaiseIntervalChanged();
 }
 
 void Options::setDelayFocusInterval(int delayFocusInterval)
 {
     if (m_focusPolicy == ClickToFocus) {
         delayFocusInterval = 0;
     }
     if (m_delayFocusInterval == delayFocusInterval) {
         return;
     }
     m_delayFocusInterval = delayFocusInterval;
     emit delayFocusIntervalChanged();
 }
 
 void Options::setShadeHover(bool shadeHover)
 {
     if (m_shadeHover == shadeHover) {
         return;
     }
     m_shadeHover = shadeHover;
     emit shadeHoverChanged();
 }
 
 void Options::setShadeHoverInterval(int shadeHoverInterval)
 {
     if (m_shadeHoverInterval == shadeHoverInterval) {
         return;
     }
     m_shadeHoverInterval = shadeHoverInterval;
     emit shadeHoverIntervalChanged();
 }
 
 void Options::setSeparateScreenFocus(bool separateScreenFocus)
 {
     if (m_separateScreenFocus == separateScreenFocus) {
         return;
     }
     m_separateScreenFocus = separateScreenFocus;
     emit separateScreenFocusChanged(m_separateScreenFocus);
 }
 
 void Options::setPlacement(int placement)
 {
     if (m_placement == static_cast<Placement::Policy>(placement)) {
         return;
     }
     m_placement = static_cast<Placement::Policy>(placement);
     emit placementChanged();
 }
 
 void Options::setBorderSnapZone(int borderSnapZone)
 {
     if (m_borderSnapZone == borderSnapZone) {
         return;
     }
     m_borderSnapZone = borderSnapZone;
     emit borderSnapZoneChanged();
 }
 
 void Options::setWindowSnapZone(int windowSnapZone)
 {
     if (m_windowSnapZone == windowSnapZone) {
         return;
     }
     m_windowSnapZone = windowSnapZone;
     emit windowSnapZoneChanged();
 }
 
 void Options::setCenterSnapZone(int centerSnapZone)
 {
     if (m_centerSnapZone == centerSnapZone) {
         return;
     }
     m_centerSnapZone = centerSnapZone;
     emit centerSnapZoneChanged();
 }
 
 void Options::setSnapOnlyWhenOverlapping(bool snapOnlyWhenOverlapping)
 {
     if (m_snapOnlyWhenOverlapping == snapOnlyWhenOverlapping) {
         return;
     }
     m_snapOnlyWhenOverlapping = snapOnlyWhenOverlapping;
     emit snapOnlyWhenOverlappingChanged();
 }
 
 void Options::setRollOverDesktops(bool rollOverDesktops)
 {
     if (m_rollOverDesktops == rollOverDesktops) {
         return;
     }
     m_rollOverDesktops = rollOverDesktops;
     emit rollOverDesktopsChanged(m_rollOverDesktops);
 }
 
 void Options::setFocusStealingPreventionLevel(int focusStealingPreventionLevel)
 {
     if (!focusPolicyIsReasonable()) {
         focusStealingPreventionLevel = 0;
     }
     if (m_focusStealingPreventionLevel == focusStealingPreventionLevel) {
         return;
     }
     m_focusStealingPreventionLevel = qMax(0, qMin(4, focusStealingPreventionLevel));
     emit focusStealingPreventionLevelChanged();
 }
 
 void Options::setLegacyFullscreenSupport(bool legacyFullscreenSupport)
 {
     if (m_legacyFullscreenSupport == legacyFullscreenSupport) {
         return;
     }
     m_legacyFullscreenSupport = legacyFullscreenSupport;
     emit legacyFullscreenSupportChanged();
 }
 
 void Options::setOperationTitlebarDblClick(WindowOperation operationTitlebarDblClick)
 {
     if (OpTitlebarDblClick == operationTitlebarDblClick) {
         return;
     }
     OpTitlebarDblClick = operationTitlebarDblClick;
     emit operationTitlebarDblClickChanged();
 }
 
 void Options::setOperationMaxButtonLeftClick(WindowOperation op)
 {
     if (opMaxButtonLeftClick == op) {
         return;
     }
     opMaxButtonLeftClick = op;
     emit operationMaxButtonLeftClickChanged();
 }
 
 void Options::setOperationMaxButtonRightClick(WindowOperation op)
 {
     if (opMaxButtonRightClick == op) {
         return;
     }
     opMaxButtonRightClick = op;
     emit operationMaxButtonRightClickChanged();
 }
 
 void Options::setOperationMaxButtonMiddleClick(WindowOperation op)
 {
     if (opMaxButtonMiddleClick == op) {
         return;
     }
     opMaxButtonMiddleClick = op;
     emit operationMaxButtonMiddleClickChanged();
 }
 
 void Options::setCommandActiveTitlebar1(MouseCommand commandActiveTitlebar1)
 {
     if (CmdActiveTitlebar1 == commandActiveTitlebar1) {
         return;
     }
     CmdActiveTitlebar1 = commandActiveTitlebar1;
     emit commandActiveTitlebar1Changed();
 }
 
 void Options::setCommandActiveTitlebar2(MouseCommand commandActiveTitlebar2)
 {
     if (CmdActiveTitlebar2 == commandActiveTitlebar2) {
         return;
     }
     CmdActiveTitlebar2 = commandActiveTitlebar2;
     emit commandActiveTitlebar2Changed();
 }
 
 void Options::setCommandActiveTitlebar3(MouseCommand commandActiveTitlebar3)
 {
     if (CmdActiveTitlebar3 == commandActiveTitlebar3) {
         return;
     }
     CmdActiveTitlebar3 = commandActiveTitlebar3;
     emit commandActiveTitlebar3Changed();
 }
 
 void Options::setCommandInactiveTitlebar1(MouseCommand commandInactiveTitlebar1)
 {
     if (CmdInactiveTitlebar1 == commandInactiveTitlebar1) {
         return;
     }
     CmdInactiveTitlebar1 = commandInactiveTitlebar1;
     emit commandInactiveTitlebar1Changed();
 }
 
 void Options::setCommandInactiveTitlebar2(MouseCommand commandInactiveTitlebar2)
 {
     if (CmdInactiveTitlebar2 == commandInactiveTitlebar2) {
         return;
     }
     CmdInactiveTitlebar2 = commandInactiveTitlebar2;
     emit commandInactiveTitlebar2Changed();
 }
 
 void Options::setCommandInactiveTitlebar3(MouseCommand commandInactiveTitlebar3)
 {
     if (CmdInactiveTitlebar3 == commandInactiveTitlebar3) {
         return;
     }
     CmdInactiveTitlebar3 = commandInactiveTitlebar3;
     emit commandInactiveTitlebar3Changed();
 }
 
 void Options::setCommandWindow1(MouseCommand commandWindow1)
 {
     if (CmdWindow1 == commandWindow1) {
         return;
     }
     CmdWindow1 = commandWindow1;
     emit commandWindow1Changed();
 }
 
 void Options::setCommandWindow2(MouseCommand commandWindow2)
 {
     if (CmdWindow2 == commandWindow2) {
         return;
     }
     CmdWindow2 = commandWindow2;
     emit commandWindow2Changed();
 }
 
 void Options::setCommandWindow3(MouseCommand commandWindow3)
 {
     if (CmdWindow3 == commandWindow3) {
         return;
     }
     CmdWindow3 = commandWindow3;
     emit commandWindow3Changed();
 }
 
 void Options::setCommandWindowWheel(MouseCommand commandWindowWheel)
 {
     if (CmdWindowWheel == commandWindowWheel) {
         return;
     }
     CmdWindowWheel = commandWindowWheel;
     emit commandWindowWheelChanged();
 }
 
 void Options::setCommandAll1(MouseCommand commandAll1)
 {
     if (CmdAll1 == commandAll1) {
         return;
     }
     CmdAll1 = commandAll1;
     emit commandAll1Changed();
 }
 
 void Options::setCommandAll2(MouseCommand commandAll2)
 {
     if (CmdAll2 == commandAll2) {
         return;
     }
     CmdAll2 = commandAll2;
     emit commandAll2Changed();
 }
 
 void Options::setCommandAll3(MouseCommand commandAll3)
 {
     if (CmdAll3 == commandAll3) {
         return;
     }
     CmdAll3 = commandAll3;
     emit commandAll3Changed();
 }
 
 void Options::setKeyCmdAllModKey(uint keyCmdAllModKey)
 {
     if (CmdAllModKey == keyCmdAllModKey) {
         return;
     }
     CmdAllModKey = keyCmdAllModKey;
     emit keyCmdAllModKeyChanged();
 }
 
 void Options::setShowGeometryTip(bool showGeometryTip)
 {
     if (show_geometry_tip == showGeometryTip) {
         return;
     }
     show_geometry_tip = showGeometryTip;
     emit showGeometryTipChanged();
 }
 
 void Options::setCondensedTitle(bool condensedTitle)
 {
     if (condensed_title == condensedTitle) {
         return;
     }
     condensed_title = condensedTitle;
     emit condensedTitleChanged();
 }
 
 void Options::setElectricBorderMaximize(bool electricBorderMaximize)
 {
     if (electric_border_maximize == electricBorderMaximize) {
         return;
     }
     electric_border_maximize = electricBorderMaximize;
     emit electricBorderMaximizeChanged();
 }
 
 void Options::setElectricBorderTiling(bool electricBorderTiling)
 {
     if (electric_border_tiling == electricBorderTiling) {
         return;
     }
     electric_border_tiling = electricBorderTiling;
     emit electricBorderTilingChanged();
 }
 
 void Options::setElectricBorderCornerRatio(float electricBorderCornerRatio)
 {
     if (electric_border_corner_ratio == electricBorderCornerRatio) {
         return;
     }
     electric_border_corner_ratio = electricBorderCornerRatio;
     emit electricBorderCornerRatioChanged();
 }
 
 void Options::setBorderlessMaximizedWindows(bool borderlessMaximizedWindows)
 {
     if (borderless_maximized_windows == borderlessMaximizedWindows) {
         return;
     }
     borderless_maximized_windows = borderlessMaximizedWindows;
     emit borderlessMaximizedWindowsChanged();
 }
 
 void Options::setKillPingTimeout(int killPingTimeout)
 {
     if (m_killPingTimeout == killPingTimeout) {
         return;
     }
     m_killPingTimeout = killPingTimeout;
     emit killPingTimeoutChanged();
 }
 
 void Options::setHideUtilityWindowsForInactive(bool hideUtilityWindowsForInactive)
 {
     if (m_hideUtilityWindowsForInactive == hideUtilityWindowsForInactive) {
         return;
     }
     m_hideUtilityWindowsForInactive = hideUtilityWindowsForInactive;
     emit hideUtilityWindowsForInactiveChanged();
 }
 
 void Options::setInactiveTabsSkipTaskbar(bool inactiveTabsSkipTaskbar)
 {
     if (m_inactiveTabsSkipTaskbar == inactiveTabsSkipTaskbar) {
         return;
     }
     m_inactiveTabsSkipTaskbar = inactiveTabsSkipTaskbar;
     emit inactiveTabsSkipTaskbarChanged();
 }
 
 void Options::setAutogroupSimilarWindows(bool autogroupSimilarWindows)
 {
     if (m_autogroupSimilarWindows == autogroupSimilarWindows) {
         return;
     }
     m_autogroupSimilarWindows = autogroupSimilarWindows;
     emit autogroupSimilarWindowsChanged();
 }
 
 void Options::setAutogroupInForeground(bool autogroupInForeground)
 {
     if (m_autogroupInForeground == autogroupInForeground) {
         return;
     }
     m_autogroupInForeground = autogroupInForeground;
     emit autogroupInForegroundChanged();
 }
 
 void Options::setCompositingMode(int compositingMode)
 {
     if (m_compositingMode == static_cast<CompositingType>(compositingMode)) {
         return;
     }
     m_compositingMode = static_cast<CompositingType>(compositingMode);
     emit compositingModeChanged();
 }
 
 void Options::setUseCompositing(bool useCompositing)
 {
     if (m_useCompositing == useCompositing) {
         return;
     }
     m_useCompositing = useCompositing;
     emit useCompositingChanged();
 }
 
 void Options::setCompositingInitialized(bool compositingInitialized)
 {
     if (m_compositingInitialized == compositingInitialized) {
         return;
     }
     m_compositingInitialized = compositingInitialized;
     emit compositingInitializedChanged();
 }
 
 void Options::setHiddenPreviews(int hiddenPreviews)
 {
     if (m_hiddenPreviews == static_cast<HiddenPreviews>(hiddenPreviews)) {
         return;
     }
     m_hiddenPreviews = static_cast<HiddenPreviews>(hiddenPreviews);
     emit hiddenPreviewsChanged();
 }
 
 void Options::setUnredirectFullscreen(bool unredirectFullscreen)
 {
     if (GLPlatform::instance()->driver() == Driver_Intel)
         unredirectFullscreen = false; // bug #252817
     if (m_unredirectFullscreen == unredirectFullscreen) {
         return;
     }
     if (GLPlatform::instance()->driver() == Driver_Intel) { // write back the value
         KConfigGroup(m_settings->config(), "Compositing").writeEntry("UnredirectFullscreen", false);
     }
     m_unredirectFullscreen = unredirectFullscreen;
     emit unredirectFullscreenChanged();
 }
 
 void Options::setGlSmoothScale(int glSmoothScale)
 {
     if (m_glSmoothScale == glSmoothScale) {
         return;
     }
     m_glSmoothScale = glSmoothScale;
     emit glSmoothScaleChanged();
 }
 
 void Options::setColorCorrected(bool colorCorrected)
 {
     if (m_colorCorrected == colorCorrected) {
         return;
     }
     m_colorCorrected = colorCorrected;
     emit colorCorrectedChanged();
 }
 
 void Options::setXrenderSmoothScale(bool xrenderSmoothScale)
 {
     if (m_xrenderSmoothScale == xrenderSmoothScale) {
         return;
     }
     m_xrenderSmoothScale = xrenderSmoothScale;
     emit xrenderSmoothScaleChanged();
 }
 
 void Options::setMaxFpsInterval(qint64 maxFpsInterval)
 {
     if (m_maxFpsInterval == maxFpsInterval) {
         return;
     }
     m_maxFpsInterval = maxFpsInterval;
     emit maxFpsIntervalChanged();
 }
 
 void Options::setRefreshRate(uint refreshRate)
 {
     if (m_refreshRate == refreshRate) {
         return;
     }
     m_refreshRate = refreshRate;
     emit refreshRateChanged();
 }
 
 void Options::setVBlankTime(qint64 vBlankTime)
 {
     if (m_vBlankTime == vBlankTime) {
         return;
     }
     m_vBlankTime = vBlankTime;
     emit vBlankTimeChanged();
 }
 
 void Options::setGlStrictBinding(bool glStrictBinding)
 {
     if (m_glStrictBinding == glStrictBinding) {
         return;
     }
     m_glStrictBinding = glStrictBinding;
     emit glStrictBindingChanged();
 }
 
 void Options::setGlStrictBindingFollowsDriver(bool glStrictBindingFollowsDriver)
 {
     if (m_glStrictBindingFollowsDriver == glStrictBindingFollowsDriver) {
         return;
     }
     m_glStrictBindingFollowsDriver = glStrictBindingFollowsDriver;
     emit glStrictBindingFollowsDriverChanged();
 }
 
 void Options::setGLCoreProfile(bool value)
 {
     if (m_glCoreProfile == value) {
         return;
     }
     m_glCoreProfile = value;
     emit glCoreProfileChanged();
 }
 
 void Options::setGlPreferBufferSwap(char glPreferBufferSwap)
 {
     if (glPreferBufferSwap == 'a') {
         // buffer cpying is very fast with the nvidia blob
         // but due to restrictions in DRI2 *incredibly* slow for all MESA drivers
         // see http://www.x.org/releases/X11R7.7/doc/dri2proto/dri2proto.txt, item 2.5
         if (GLPlatform::instance()->driver() == Driver_NVidia)
             glPreferBufferSwap = CopyFrontBuffer;
         else if (GLPlatform::instance()->driver() != Driver_Unknown) // undetected, finally resolved when context is initialized
             glPreferBufferSwap = ExtendDamage;
     }
     if (m_glPreferBufferSwap == (GlSwapStrategy)glPreferBufferSwap) {
         return;
     }
     m_glPreferBufferSwap = (GlSwapStrategy)glPreferBufferSwap;
     emit glPreferBufferSwapChanged();
 }
 
 void Options::setGlPlatformInterface(OpenGLPlatformInterface interface)
 {
     // check environment variable
     const QByteArray envOpenGLInterface(qgetenv("KWIN_OPENGL_INTERFACE"));
     if (!envOpenGLInterface.isEmpty()) {
         if (qstrcmp(envOpenGLInterface, "egl") == 0) {
             qCDebug(KWIN_CORE) << "Forcing EGL native interface through environment variable";
             interface = EglPlatformInterface;
         } else if (qstrcmp(envOpenGLInterface, "glx") == 0) {
             qCDebug(KWIN_CORE) << "Forcing GLX native interface through environment variable";
             interface = GlxPlatformInterface;
         }
     }
     if (kwinApp()->shouldUseWaylandForCompositing() && interface == GlxPlatformInterface) {
         // Glx is impossible on Wayland, enforce egl
         qCDebug(KWIN_CORE) << "Forcing EGL native interface for Wayland mode";
         interface = EglPlatformInterface;
     }
 #if !HAVE_EPOXY_GLX
     qCDebug(KWIN_CORE) << "Forcing EGL native interface as compiled without GLX support";
     interface = EglPlatformInterface;
 #endif
     if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGLES) {
         qCDebug(KWIN_CORE) << "Forcing EGL native interface as Qt uses OpenGL ES";
         interface = EglPlatformInterface;
     } else if (qstrcmp(qgetenv("KWIN_COMPOSE"), "O2ES") == 0) {
         qCDebug(KWIN_CORE) << "Forcing EGL native interface as OpenGL ES requested through KWIN_COMPOSE environment variable.";
         interface = EglPlatformInterface;
     }
 
     if (m_glPlatformInterface == interface) {
         return;
     }
     m_glPlatformInterface = interface;
     emit glPlatformInterfaceChanged();
 }
 
 void Options::reparseConfiguration()
 {
     m_settings->config()->reparseConfiguration();
 }
 
 void Options::updateSettings()
 {
     loadConfig();
     // Read button tooltip animation effect from kdeglobals
     // Since we want to allow users to enable window decoration tooltips
     // and not kstyle tooltips and vise-versa, we don't read the
     // "EffectNoTooltip" setting from kdeglobals.
 
 
 //    QToolTip::setGloballyEnabled( d->show_tooltips );
 // KDE4 this probably needs to be done manually in clients
 
     // Driver-specific config detection
     setCompositingInitialized(false);
     reloadCompositingSettings();
 
     emit configChanged();
 }
 
 void Options::loadConfig()
 {
     m_settings->load();
 
     syncFromKcfgc();
 
     // Electric borders
     KConfigGroup config(m_settings->config(), "Windows");
     OpTitlebarDblClick = windowOperation(config.readEntry("TitlebarDoubleClickCommand", "Maximize"), true);
     setOperationMaxButtonLeftClick(windowOperation(config.readEntry("MaximizeButtonLeftClickCommand", "Maximize"), true));
     setOperationMaxButtonMiddleClick(windowOperation(config.readEntry("MaximizeButtonMiddleClickCommand", "Maximize (vertical only)"), true));
     setOperationMaxButtonRightClick(windowOperation(config.readEntry("MaximizeButtonRightClickCommand", "Maximize (horizontal only)"), true));
 
     // Mouse bindings
     config = KConfigGroup(m_settings->config(), "MouseBindings");
     // TODO: add properties for missing options
     CmdTitlebarWheel = mouseWheelCommand(config.readEntry("CommandTitlebarWheel", "Switch to Window Tab to the Left/Right"));
     CmdAllModKey = (config.readEntry("CommandAllKey", "Alt") == QStringLiteral("Meta")) ? Qt::Key_Meta : Qt::Key_Alt;
     CmdAllWheel = mouseWheelCommand(config.readEntry("CommandAllWheel", "Nothing"));
     setCommandActiveTitlebar1(mouseCommand(config.readEntry("CommandActiveTitlebar1", "Raise"), true));
     setCommandActiveTitlebar2(mouseCommand(config.readEntry("CommandActiveTitlebar2", "Start Window Tab Drag"), true));
     setCommandActiveTitlebar3(mouseCommand(config.readEntry("CommandActiveTitlebar3", "Operations menu"), true));
     setCommandInactiveTitlebar1(mouseCommand(config.readEntry("CommandInactiveTitlebar1", "Activate and raise"), true));
     setCommandInactiveTitlebar2(mouseCommand(config.readEntry("CommandInactiveTitlebar2", "Start Window Tab Drag"), true));
     setCommandInactiveTitlebar3(mouseCommand(config.readEntry("CommandInactiveTitlebar3", "Operations menu"), true));
     setCommandWindow1(mouseCommand(config.readEntry("CommandWindow1", "Activate, raise and pass click"), false));
     setCommandWindow2(mouseCommand(config.readEntry("CommandWindow2", "Activate and pass click"), false));
     setCommandWindow3(mouseCommand(config.readEntry("CommandWindow3", "Activate and pass click"), false));
     setCommandWindowWheel(mouseCommand(config.readEntry("CommandWindowWheel", "Scroll"), false));
     setCommandAll1(mouseCommand(config.readEntry("CommandAll1", "Move"), false));
     setCommandAll2(mouseCommand(config.readEntry("CommandAll2", "Toggle raise and lower"), false));
     setCommandAll3(mouseCommand(config.readEntry("CommandAll3", "Resize"), false));
 
     // TODO: should they be moved into reloadCompositingSettings?
     config = KConfigGroup(m_settings->config(), "Compositing");
     setMaxFpsInterval(1 * 1000 * 1000 * 1000 / config.readEntry("MaxFPS", Options::defaultMaxFps()));
     setRefreshRate(config.readEntry("RefreshRate", Options::defaultRefreshRate()));
     setVBlankTime(config.readEntry("VBlankTime", Options::defaultVBlankTime()) * 1000); // config in micro, value in nano resolution
 
     // Modifier Only Shortcuts
     config = KConfigGroup(m_settings->config(), "ModifierOnlyShortcuts");
     m_modifierOnlyShortcuts.clear();
     if (config.hasKey("Shift")) {
         m_modifierOnlyShortcuts.insert(Qt::ShiftModifier, config.readEntry("Shift", QStringList()));
     }
     if (config.hasKey("Control")) {
         m_modifierOnlyShortcuts.insert(Qt::ControlModifier, config.readEntry("Control", QStringList()));
     }
     if (config.hasKey("Alt")) {
         m_modifierOnlyShortcuts.insert(Qt::AltModifier, config.readEntry("Alt", QStringList()));
     }
     if (config.hasKey("Meta")) {
         m_modifierOnlyShortcuts.insert(Qt::MetaModifier, config.readEntry("Meta", QStringList()));
     }
 }
 
 void Options::syncFromKcfgc()
 {
     setShowGeometryTip(m_settings->geometryTip());
     setCondensedTitle(m_settings->condensedTitle());
     setFocusPolicy(m_settings->focusPolicy());
     setNextFocusPrefersMouse(m_settings->nextFocusPrefersMouse());
     setSeparateScreenFocus(m_settings->separateScreenFocus());
     setRollOverDesktops(m_settings->rollOverDesktops());
     setLegacyFullscreenSupport(m_settings->legacyFullscreenSupport());
     setFocusStealingPreventionLevel(m_settings->focusStealingPreventionLevel());
 
 #ifdef KWIN_BUILD_DECORATIONS
     setPlacement(m_settings->placement());
 #else
     setPlacement(Placement::Maximizing);
 #endif
 
     setAutoRaise(m_settings->autoRaise());
     setAutoRaiseInterval(m_settings->autoRaiseInterval());
     setDelayFocusInterval(m_settings->delayFocusInterval());
     setShadeHover(m_settings->shadeHover());
     setShadeHoverInterval(m_settings->shadeHoverInterval());
     setClickRaise(m_settings->clickRaise());
     setBorderSnapZone(m_settings->borderSnapZone());
     setWindowSnapZone(m_settings->windowSnapZone());
     setCenterSnapZone(m_settings->centerSnapZone());
     setSnapOnlyWhenOverlapping(m_settings->snapOnlyWhenOverlapping());
     setKillPingTimeout(m_settings->killPingTimeout());
     setHideUtilityWindowsForInactive(m_settings->hideUtilityWindowsForInactive());
     setInactiveTabsSkipTaskbar(m_settings->inactiveTabsSkipTaskbar());
     setAutogroupSimilarWindows(m_settings->autogroupSimilarWindows());
     setAutogroupInForeground(m_settings->autogroupInForeground());
     setBorderlessMaximizedWindows(m_settings->borderlessMaximizedWindows());
     setElectricBorderMaximize(m_settings->electricBorderMaximize());
     setElectricBorderTiling(m_settings->electricBorderTiling());
     setElectricBorderCornerRatio(m_settings->electricBorderCornerRatio());
 
 }
 
 bool Options::loadCompositingConfig (bool force)
 {
     KConfigGroup config(m_settings->config(), "Compositing");
 
     bool useCompositing = false;
     CompositingType compositingMode = NoCompositing;
     QString compositingBackend = config.readEntry("Backend", "OpenGL");
     if (compositingBackend == QStringLiteral("XRender"))
         compositingMode = XRenderCompositing;
     else if (compositingBackend == "QPainter")
         compositingMode = QPainterCompositing;
     else
         compositingMode = OpenGLCompositing;
 
     if (const char *c = getenv("KWIN_COMPOSE")) {
         switch(c[0]) {
         case 'O':
             qCDebug(KWIN_CORE) << "Compositing forced to OpenGL mode by environment variable";
             compositingMode = OpenGLCompositing;
             useCompositing = true;
             break;
         case 'X':
             qCDebug(KWIN_CORE) << "Compositing forced to XRender mode by environment variable";
             compositingMode = XRenderCompositing;
             useCompositing = true;
             break;
         case 'Q':
             qCDebug(KWIN_CORE) << "Compositing forced to QPainter mode by environment variable";
             compositingMode = QPainterCompositing;
             useCompositing = true;
             break;
         case 'N':
             if (getenv("KDE_FAILSAFE"))
                 qCDebug(KWIN_CORE) << "Compositing disabled forcefully by KDE failsafe mode";
             else
                 qCDebug(KWIN_CORE) << "Compositing disabled forcefully by environment variable";
             compositingMode = NoCompositing;
             break;
         default:
             qCDebug(KWIN_CORE) << "Unknown KWIN_COMPOSE mode set, ignoring";
             break;
         }
     }
     if (kwinApp()->shouldUseWaylandForCompositing() && (compositingMode == XRenderCompositing || compositingMode == NoCompositing)) {
         qCDebug(KWIN_CORE) << "Compositing forced to QPainter mode by invalid compositor selection";
         compositingMode = QPainterCompositing;
     }
     setCompositingMode(compositingMode);
 
     if (m_compositingMode == NoCompositing) {
         setUseCompositing(false);
         return false; // do not even detect compositing preferences if explicitly disabled
     }
 
     // it's either enforced by env or by initial resume from "suspend" or we check the settings
     setUseCompositing(useCompositing || force || config.readEntry("Enabled", Options::defaultUseCompositing()));
 
     if (!m_useCompositing)
         return false; // not enforced or necessary and not "enabled" by settings
     return true;
 }
 
 void Options::reloadCompositingSettings(bool force)
 {
     if (!loadCompositingConfig(force)) {
         return;
     }
     // from now on we've an initial setup and don't have to reload settings on compositing activation
     // see Workspace::setupCompositing(), composite.cpp
     setCompositingInitialized(true);
 
     // Compositing settings
     KConfigGroup config(m_settings->config(), "Compositing");
 
     setGlSmoothScale(qBound(-1, config.readEntry("GLTextureFilter", Options::defaultGlSmoothScale()), 2));
     setGlStrictBindingFollowsDriver(!config.hasKey("GLStrictBinding"));
     if (!isGlStrictBindingFollowsDriver()) {
         setGlStrictBinding(config.readEntry("GLStrictBinding", Options::defaultGlStrictBinding()));
     }
     setGLCoreProfile(config.readEntry("GLCore", Options::defaultGLCoreProfile()));
 
     char c = 0;
     const QString s = config.readEntry("GLPreferBufferSwap", QString(Options::defaultGlPreferBufferSwap()));
     if (!s.isEmpty())
         c = s.at(0).toAscii();
     if (c != 'a' && c != 'c' && c != 'p' && c != 'e')
         c = 0;
     setGlPreferBufferSwap(c);
 
     setColorCorrected(config.readEntry("GLColorCorrection", Options::defaultColorCorrected()));
 
     m_xrenderSmoothScale = config.readEntry("XRenderSmoothScale", false);
 
     HiddenPreviews previews = Options::defaultHiddenPreviews();
     // 4 - off, 5 - shown, 6 - always, other are old values
     int hps = config.readEntry("HiddenPreviews", 5);
     if (hps == 4)
         previews = HiddenPreviewsNever;
     else if (hps == 5)
         previews = HiddenPreviewsShown;
     else if (hps == 6)
         previews = HiddenPreviewsAlways;
     setHiddenPreviews(previews);
 
     setUnredirectFullscreen(config.readEntry("UnredirectFullscreen", Options::defaultUnredirectFullscreen()));
     // TOOD: add setter
     animationSpeed = qBound(0, config.readEntry("AnimationSpeed", Options::defaultAnimationSpeed()), 6);
 
     auto interfaceToKey = [](OpenGLPlatformInterface interface) {
         switch (interface) {
         case GlxPlatformInterface:
             return QStringLiteral("glx");
         case EglPlatformInterface:
             return QStringLiteral("egl");
         default:
             return QString();
         }
     };
     auto keyToInterface = [](const QString &key) {
         if (key == QStringLiteral("glx")) {
             return GlxPlatformInterface;
         } else if (key == QStringLiteral("egl")) {
             return EglPlatformInterface;
         }
         return defaultGlPlatformInterface();
     };
     setGlPlatformInterface(keyToInterface(config.readEntry("GLPlatformInterface", interfaceToKey(m_glPlatformInterface))));
 }
 
 // restricted should be true for operations that the user may not be able to repeat
 // if the window is moved out of the workspace (e.g. if the user moves a window
 // by the titlebar, and moves it too high beneath Kicker at the top edge, they
 // may not be able to move it back, unless they know about Alt+LMB)
 Options::WindowOperation Options::windowOperation(const QString &name, bool restricted)
 {
     if (name == QStringLiteral("Move"))
         return restricted ? MoveOp : UnrestrictedMoveOp;
     else if (name == QStringLiteral("Resize"))
         return restricted ? ResizeOp : UnrestrictedResizeOp;
     else if (name == QStringLiteral("Maximize"))
         return MaximizeOp;
     else if (name == QStringLiteral("Minimize"))
         return MinimizeOp;
     else if (name == QStringLiteral("Close"))
         return CloseOp;
     else if (name == QStringLiteral("OnAllDesktops"))
         return OnAllDesktopsOp;
     else if (name == QStringLiteral("Shade"))
         return ShadeOp;
     else if (name == QStringLiteral("Operations"))
         return OperationsOp;
     else if (name == QStringLiteral("Maximize (vertical only)"))
         return VMaximizeOp;
     else if (name == QStringLiteral("Maximize (horizontal only)"))
         return HMaximizeOp;
     else if (name == QStringLiteral("Lower"))
         return LowerOp;
     return NoOp;
 }
 
 Options::MouseCommand Options::mouseCommand(const QString &name, bool restricted)
 {
     QString lowerName = name.toLower();
     if (lowerName == QStringLiteral("raise")) return MouseRaise;
     if (lowerName == QStringLiteral("lower")) return MouseLower;
     if (lowerName == QStringLiteral("operations menu")) return MouseOperationsMenu;
     if (lowerName == QStringLiteral("toggle raise and lower")) return MouseToggleRaiseAndLower;
     if (lowerName == QStringLiteral("activate and raise")) return MouseActivateAndRaise;
     if (lowerName == QStringLiteral("activate and lower")) return MouseActivateAndLower;
     if (lowerName == QStringLiteral("activate")) return MouseActivate;
     if (lowerName == QStringLiteral("activate, raise and pass click")) return MouseActivateRaiseAndPassClick;
     if (lowerName == QStringLiteral("activate and pass click")) return MouseActivateAndPassClick;
     if (lowerName == QStringLiteral("scroll")) return MouseNothing;
     if (lowerName == QStringLiteral("activate and scroll")) return MouseActivateAndPassClick;
     if (lowerName == QStringLiteral("activate, raise and scroll")) return MouseActivateRaiseAndPassClick;
     if (lowerName == QStringLiteral("activate, raise and move"))
         return restricted ? MouseActivateRaiseAndMove : MouseActivateRaiseAndUnrestrictedMove;
     if (lowerName == QStringLiteral("move")) return restricted ? MouseMove : MouseUnrestrictedMove;
     if (lowerName == QStringLiteral("resize")) return restricted ? MouseResize : MouseUnrestrictedResize;
     if (lowerName == QStringLiteral("shade")) return MouseShade;
     if (lowerName == QStringLiteral("minimize")) return MouseMinimize;
     if (lowerName == QStringLiteral("start window tab drag")) return MouseDragTab;
     if (lowerName == QStringLiteral("close")) return MouseClose;
     if (lowerName == QStringLiteral("increase opacity")) return MouseOpacityMore;
     if (lowerName == QStringLiteral("decrease opacity")) return MouseOpacityLess;
     if (lowerName == QStringLiteral("nothing")) return MouseNothing;
     return MouseNothing;
 }
 
 Options::MouseWheelCommand Options::mouseWheelCommand(const QString &name)
 {
     QString lowerName = name.toLower();
     if (lowerName == QStringLiteral("raise/lower")) return MouseWheelRaiseLower;
     if (lowerName == QStringLiteral("shade/unshade")) return MouseWheelShadeUnshade;
     if (lowerName == QStringLiteral("maximize/restore")) return MouseWheelMaximizeRestore;
     if (lowerName == QStringLiteral("above/below")) return MouseWheelAboveBelow;
     if (lowerName == QStringLiteral("previous/next desktop")) return MouseWheelPreviousNextDesktop;
     if (lowerName == QStringLiteral("change opacity")) return MouseWheelChangeOpacity;
     if (lowerName == QStringLiteral("switch to window tab to the left/right")) return MouseWheelChangeCurrentTab;
     if (lowerName == QStringLiteral("nothing")) return MouseWheelNothing;
     return MouseWheelChangeCurrentTab;
 }
 
 bool Options::showGeometryTip() const
 {
     return show_geometry_tip;
 }
 
 bool Options::condensedTitle() const
 {
     return condensed_title;
 }
 
 Options::MouseCommand Options::wheelToMouseCommand(MouseWheelCommand com, int delta) const
 {
     switch(com) {
     case MouseWheelRaiseLower:
         return delta > 0 ? MouseRaise : MouseLower;
     case MouseWheelShadeUnshade:
         return delta > 0 ? MouseSetShade : MouseUnsetShade;
     case MouseWheelMaximizeRestore:
         return delta > 0 ? MouseMaximize : MouseRestore;
     case MouseWheelAboveBelow:
         return delta > 0 ? MouseAbove : MouseBelow;
     case MouseWheelPreviousNextDesktop:
         return delta > 0 ? MousePreviousDesktop : MouseNextDesktop;
     case MouseWheelChangeOpacity:
         return delta > 0 ? MouseOpacityMore : MouseOpacityLess;
     case MouseWheelChangeCurrentTab:
         return delta > 0 ? MousePreviousTab : MouseNextTab;
     default:
         return MouseNothing;
     }
 }
 #endif
 
 double Options::animationTimeFactor() const
 {
     const double factors[] = { 0, 0.2, 0.5, 1, 2, 4, 20 };
     return factors[ animationSpeed ];
 }
 
 Options::WindowOperation Options::operationMaxButtonClick(Qt::MouseButtons button) const
 {
     return button == Qt::RightButton ? opMaxButtonRightClick :
            button == Qt::MidButton ?   opMaxButtonMiddleClick :
            opMaxButtonLeftClick;
 }
 
 QStringList Options::modifierOnlyDBusShortcut(Qt::KeyboardModifier mod) const
 {
     return m_modifierOnlyShortcuts.value(mod);
 }
 
 bool Options::isUseCompositing() const
 {
     return m_useCompositing || kwinApp()->platform()->requiresCompositing();
 }
 
 
 bool Options::isUnredirectFullscreen() const
 {
     return m_unredirectFullscreen && !kwinApp()->platform()->requiresCompositing();
 }
 
 } // namespace
diff --git a/platform.cpp b/platform.cpp
index 1273df848..736e38446 100644
--- a/platform.cpp
+++ b/platform.cpp
@@ -1,289 +1,304 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2015 Martin Gräßlin <mgraesslin@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "platform.h"
 #include <config-kwin.h>
 #include "abstract_egl_backend.h"
 #include "composite.h"
 #include "cursor.h"
 #include "input.h"
 #include "pointer_input.h"
 #include "scene_opengl.h"
 #include "screenedge.h"
 #include "wayland_server.h"
 
 namespace KWin
 {
 
 Platform::Platform(QObject *parent)
     : QObject(parent)
 {
 }
 
 Platform::~Platform()
 {
 }
 
 QImage Platform::softwareCursor() const
 {
     return input()->pointer()->cursorImage();
 }
 
 QPoint Platform::softwareCursorHotspot() const
 {
     return input()->pointer()->cursorHotSpot();
 }
 
 Screens *Platform::createScreens(QObject *parent)
 {
     Q_UNUSED(parent)
     return nullptr;
 }
 
 OpenGLBackend *Platform::createOpenGLBackend()
 {
     return nullptr;
 }
 
 QPainterBackend *Platform::createQPainterBackend()
 {
     return nullptr;
 }
 
 Edge *Platform::createScreenEdge(ScreenEdges *edges)
 {
     return new Edge(edges);
 }
 
 void Platform::configurationChangeRequested(KWayland::Server::OutputConfigurationInterface *config)
 {
     Q_UNUSED(config)
     qCWarning(KWIN_CORE) << "This backend does not support configuration changes.";
 }
 
 void Platform::setSoftWareCursor(bool set)
 {
     if (m_softWareCursor == set) {
         return;
     }
     m_softWareCursor = set;
     if (m_softWareCursor) {
         connect(Cursor::self(), &Cursor::posChanged, this, &Platform::triggerCursorRepaint);
     } else {
         disconnect(Cursor::self(), &Cursor::posChanged, this, &Platform::triggerCursorRepaint);
     }
 }
 
 void Platform::triggerCursorRepaint()
 {
     if (!Compositor::self()) {
         return;
     }
     const QPoint &hotSpot = softwareCursorHotspot();
     const QSize &size = softwareCursor().size();
     Compositor::self()->addRepaint(m_cursor.lastRenderedPosition.x() - hotSpot.x(),
                                    m_cursor.lastRenderedPosition.y() - hotSpot.y(),
                                    size.width(), size.height());
 }
 
 void Platform::markCursorAsRendered()
 {
     if (m_softWareCursor) {
         m_cursor.lastRenderedPosition = Cursor::pos();
     }
     if (input()->pointer()) {
         input()->pointer()->markCursorAsRendered();
     }
 }
 
 void Platform::keyboardKeyPressed(quint32 key, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processKeyboardKey(key, InputRedirection::KeyboardKeyPressed, time);
 }
 
 void Platform::keyboardKeyReleased(quint32 key, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processKeyboardKey(key, InputRedirection::KeyboardKeyReleased, time);
 }
 
 void Platform::keyboardModifiers(uint32_t modsDepressed, uint32_t modsLatched, uint32_t modsLocked, uint32_t group)
 {
     if (!input()) {
         return;
     }
     input()->processKeyboardModifiers(modsDepressed, modsLatched, modsLocked, group);
 }
 
 void Platform::keymapChange(int fd, uint32_t size)
 {
     if (!input()) {
         return;
     }
     input()->processKeymapChange(fd, size);
 }
 
 void Platform::pointerAxisHorizontal(qreal delta, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processPointerAxis(InputRedirection::PointerAxisHorizontal, delta, time);
 }
 
 void Platform::pointerAxisVertical(qreal delta, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processPointerAxis(InputRedirection::PointerAxisVertical, delta, time);
 }
 
 void Platform::pointerButtonPressed(quint32 button, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processPointerButton(button, InputRedirection::PointerButtonPressed, time);
 }
 
 void Platform::pointerButtonReleased(quint32 button, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processPointerButton(button, InputRedirection::PointerButtonReleased, time);
 }
 
 void Platform::pointerMotion(const QPointF &position, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processPointerMotion(position, time);
 }
 
 void Platform::touchCancel()
 {
     if (!input()) {
         return;
     }
     input()->cancelTouch();
 }
 
 void Platform::touchDown(qint32 id, const QPointF &pos, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processTouchDown(id, pos, time);
 }
 
 void Platform::touchFrame()
 {
     if (!input()) {
         return;
     }
     input()->touchFrame();
 }
 
 void Platform::touchMotion(qint32 id, const QPointF &pos, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processTouchMotion(id, pos, time);
 }
 
 void Platform::touchUp(qint32 id, quint32 time)
 {
     if (!input()) {
         return;
     }
     input()->processTouchUp(id, time);
 }
 
 void Platform::repaint(const QRect &rect)
 {
     if (!Compositor::self()) {
         return;
     }
     Compositor::self()->addRepaint(rect);
 }
 
 void Platform::setReady(bool ready)
 {
     if (m_ready == ready) {
         return;
     }
     m_ready = ready;
     emit readyChanged(m_ready);
 }
 
 void Platform::warpPointer(const QPointF &globalPos)
 {
     Q_UNUSED(globalPos)
 }
 
 bool Platform::supportsQpaContext() const
 {
     return hasGLExtension(QByteArrayLiteral("EGL_KHR_surfaceless_context"));
 }
 
 EGLDisplay Platform::sceneEglDisplay() const
 {
     if (Compositor *c = Compositor::self()) {
         if (SceneOpenGL *s = dynamic_cast<SceneOpenGL*>(c->scene())) {
             return static_cast<AbstractEglBackend*>(s->backend())->eglDisplay();
         }
     }
     return EGL_NO_DISPLAY;
 }
 
 EGLContext Platform::sceneEglContext() const
 {
     if (Compositor *c = Compositor::self()) {
         if (SceneOpenGL *s = dynamic_cast<SceneOpenGL*>(c->scene())) {
             return static_cast<AbstractEglBackend*>(s->backend())->context();
         }
     }
     return EGL_NO_CONTEXT;
 }
 
 QSize Platform::screenSize() const
 {
     return QSize();
 }
 
 QVector<QRect> Platform::screenGeometries() const
 {
     return QVector<QRect>({QRect(QPoint(0, 0), screenSize())});
 }
 
 bool Platform::requiresCompositing() const
 {
     return true;
 }
 
+bool Platform::compositingPossible() const
+{
+    return true;
+}
+
+QString Platform::compositingNotPossibleReason() const
+{
+    return QString();
+}
+
+bool Platform::openGLCompositingIsBroken() const
+{
+    return false;
+}
+
 }
diff --git a/platform.h b/platform.h
index 036874268..b865afc86 100644
--- a/platform.h
+++ b/platform.h
@@ -1,202 +1,226 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2015 Martin Gräßlin <mgraesslin@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #ifndef KWIN_PLATFORM_H
 #define KWIN_PLATFORM_H
 #include <kwin_export.h>
 #include <epoxy/egl.h>
 #include <fixx11h.h>
 #include <QImage>
 #include <QObject>
 
 namespace KWayland {
     namespace Server {
         class OutputConfigurationInterface;
     }
 }
 
 namespace KWin
 {
 
 class Edge;
 class OpenGLBackend;
 class QPainterBackend;
 class Screens;
 class ScreenEdges;
 class WaylandCursorTheme;
 
 class KWIN_EXPORT Platform : public QObject
 {
     Q_OBJECT
 public:
     virtual ~Platform();
 
     virtual void init() = 0;
     virtual Screens *createScreens(QObject *parent = nullptr);
     virtual OpenGLBackend *createOpenGLBackend();
     virtual QPainterBackend *createQPainterBackend();
     /**
      * Allows the platform to create a platform specific screen edge.
      * The default implementation creates a Edge.
      **/
     virtual Edge *createScreenEdge(ScreenEdges *parent);
     virtual void warpPointer(const QPointF &globalPos);
     /**
      * Whether our Compositing EGL display allows a surface less context
      * so that a sharing context could be created.
      **/
     virtual bool supportsQpaContext() const;
     /**
      * The EGLDisplay used by the compositing scene.
      **/
     virtual EGLDisplay sceneEglDisplay() const;
     /**
      * The EGLContext used by the compositing scene.
      **/
     virtual EGLContext sceneEglContext() const;
 
     /**
      * Implementing subclasses should provide a size in case the backend represents
      * a basic screen and uses the BasicScreens.
      *
      * Base implementation returns an invalid size.
      **/
     virtual QSize screenSize() const;
     /**
      * Implementing subclasses should provide all geometries in case the backend represents
      * a basic screen and uses the BasicScreens.
      *
      * Base implementation returns one QRect positioned at 0/0 with screenSize() as size.
      **/
     virtual QVector<QRect> screenGeometries() const;
     /**
      * Implement this method to receive configuration change requests through KWayland's
      * OutputManagement interface.
      *
      * Base implementation warns that the current backend does not implement this
      * functionality.
      */
     virtual void configurationChangeRequested(KWayland::Server::OutputConfigurationInterface *config);
 
     /**
      * Whether the Platform requires compositing for rendering.
      * Default implementation returns @c true. If the implementing Platform allows to be used
      * without compositing (e.g. rendering is done by the windowing system), re-implement this method.
      **/
     virtual bool requiresCompositing() const;
+    /**
+     * Whether Compositing is possible in the Platform.
+     * Returning @c false in this method makes only sense if @link{requiresCompositing} returns @c false.
+     *
+     * The default implementation returns @c true.
+     * @see requiresCompositing
+     **/
+    virtual bool compositingPossible() const;
+    /**
+     * Returns a user facing text explaining why compositing is not possible in case
+     * @link{compositingPossible} returns @c false.
+     *
+     * The default implementation returns an empty string.
+     * @see compositingPossible
+     **/
+    virtual QString compositingNotPossibleReason() const;
+    /**
+     * Whether OpenGL compositing is broken.
+     * The Platform can implement this method if it is able to detect whether OpenGL compositing
+     * broke (e.g. triggered a crash in a previous run).
+     *
+     * Default implementation returns @c false.
+     **/
+    virtual bool openGLCompositingIsBroken() const;
 
     bool usesSoftwareCursor() const {
         return m_softWareCursor;
     }
     QImage softwareCursor() const;
     QPoint softwareCursorHotspot() const;
     void markCursorAsRendered();
 
     bool handlesOutputs() const {
         return m_handlesOutputs;
     }
     bool isReady() const {
         return m_ready;
     }
     void setInitialWindowSize(const QSize &size) {
         m_initialWindowSize = size;
     }
     void setDeviceIdentifier(const QByteArray &identifier) {
         m_deviceIdentifier = identifier;
     }
     bool supportsPointerWarping() const {
         return m_pointerWarping;
     }
     bool areOutputsEnabled() const {
         return m_outputsEnabled;
     }
     void setOutputsEnabled(bool enabled) {
         m_outputsEnabled = enabled;
     }
     int initialOutputCount() const {
         return m_initialOutputCount;
     }
     void setInitialOutputCount(int count) {
         m_initialOutputCount = count;
     }
 
 public Q_SLOTS:
     void pointerMotion(const QPointF &position, quint32 time);
     void pointerButtonPressed(quint32 button, quint32 time);
     void pointerButtonReleased(quint32 button, quint32 time);
     void pointerAxisHorizontal(qreal delta, quint32 time);
     void pointerAxisVertical(qreal delta, quint32 time);
     void keyboardKeyPressed(quint32 key, quint32 time);
     void keyboardKeyReleased(quint32 key, quint32 time);
     void keyboardModifiers(uint32_t modsDepressed, uint32_t modsLatched, uint32_t modsLocked, uint32_t group);
     void keymapChange(int fd, uint32_t size);
     void touchDown(qint32 id, const QPointF &pos, quint32 time);
     void touchUp(qint32 id, quint32 time);
     void touchMotion(qint32 id, const QPointF &pos, quint32 time);
     void touchCancel();
     void touchFrame();
 
 Q_SIGNALS:
     void screensQueried();
     void initFailed();
     void cursorChanged();
     void readyChanged(bool);
     /**
      * Emitted by backends using a one screen (nested window) approach and when the size of that changes.
      **/
     void screenSizeChanged();
 
 protected:
     explicit Platform(QObject *parent = nullptr);
     void setSoftWareCursor(bool set);
     void handleOutputs() {
         m_handlesOutputs = true;
     }
     void repaint(const QRect &rect);
     void setReady(bool ready);
     QSize initialWindowSize() const {
         return m_initialWindowSize;
     }
     QByteArray deviceIdentifier() const {
         return m_deviceIdentifier;
     }
     void setSupportsPointerWarping(bool set) {
         m_pointerWarping = set;
     }
 
 private:
     void triggerCursorRepaint();
     bool m_softWareCursor = false;
     struct {
         QPoint lastRenderedPosition;
     } m_cursor;
     bool m_handlesOutputs = false;
     bool m_ready = false;
     QSize m_initialWindowSize;
     QByteArray m_deviceIdentifier;
     bool m_pointerWarping = false;
     bool m_outputsEnabled = true;
     int m_initialOutputCount = 1;
 };
 
 }
 
 Q_DECLARE_INTERFACE(KWin::Platform, "org.kde.kwin.Platform")
 
 #endif
diff --git a/plugins/platforms/x11/standalone/x11_platform.cpp b/plugins/platforms/x11/standalone/x11_platform.cpp
index fa090a886..269842612 100644
--- a/plugins/platforms/x11/standalone/x11_platform.cpp
+++ b/plugins/platforms/x11/standalone/x11_platform.cpp
@@ -1,83 +1,158 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2016 Martin Gräßlin <mgraesslin@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "x11_platform.h"
 #include "edge.h"
 #include <kwinconfig.h>
 #if HAVE_EPOXY_GLX
 #include "glxbackend.h"
 #endif
 #include "eglonxbackend.h"
 #include "screens_xrandr.h"
 #include "options.h"
 
+#include <KConfigGroup>
+#include <KLocalizedString>
+
+#include <QOpenGLContext>
 #include <QX11Info>
 
 namespace KWin
 {
 
 X11StandalonePlatform::X11StandalonePlatform(QObject *parent)
     : Platform(parent)
 {
 }
 
 X11StandalonePlatform::~X11StandalonePlatform() = default;
 
 void X11StandalonePlatform::init()
 {
     if (!QX11Info::isPlatformX11()) {
         emit initFailed();
         return;
     }
     setReady(true);
     emit screensQueried();
 }
 
 Screens *X11StandalonePlatform::createScreens(QObject *parent)
 {
     return new XRandRScreens(parent);
 }
 
 OpenGLBackend *X11StandalonePlatform::createOpenGLBackend()
 {
     switch (options->glPlatformInterface()) {
 #if HAVE_EPOXY_GLX
     case GlxPlatformInterface:
         return new GlxBackend();
 #endif
     case EglPlatformInterface:
         return new EglOnXBackend();
     default:
         // no backend available
         return nullptr;
     }
 }
 
 Edge *X11StandalonePlatform::createScreenEdge(ScreenEdges *edges)
 {
     return new WindowBasedEdge(edges);
 }
 
 bool X11StandalonePlatform::requiresCompositing() const
 {
     return false;
 }
 
+bool X11StandalonePlatform::openGLCompositingIsBroken() const
+{
+    const QString unsafeKey(QLatin1String("OpenGLIsUnsafe") + (kwinApp()->isX11MultiHead() ? QString::number(kwinApp()->x11ScreenNumber()) : QString()));
+    return KConfigGroup(kwinApp()->config(), "Compositing").readEntry(unsafeKey, false);
+}
+
+QString X11StandalonePlatform::compositingNotPossibleReason() const
+{
+    // first off, check whether we figured that we'll crash on detection because of a buggy driver
+    KConfigGroup gl_workaround_group(kwinApp()->config(), "Compositing");
+    const QString unsafeKey(QLatin1String("OpenGLIsUnsafe") + (kwinApp()->isX11MultiHead() ? QString::number(kwinApp()->x11ScreenNumber()) : QString()));
+    if (gl_workaround_group.readEntry("Backend", "OpenGL") == QLatin1String("OpenGL") &&
+        gl_workaround_group.readEntry(unsafeKey, false))
+        return i18n("<b>OpenGL compositing (the default) has crashed KWin in the past.</b><br>"
+                    "This was most likely due to a driver bug."
+                    "<p>If you think that you have meanwhile upgraded to a stable driver,<br>"
+                    "you can reset this protection but <b>be aware that this might result in an immediate crash!</b></p>"
+                    "<p>Alternatively, you might want to use the XRender backend instead.</p>");
+
+    if (!Xcb::Extensions::self()->isCompositeAvailable() || !Xcb::Extensions::self()->isDamageAvailable()) {
+        return i18n("Required X extensions (XComposite and XDamage) are not available.");
+    }
+#if !defined( KWIN_HAVE_XRENDER_COMPOSITING )
+    if (!hasGlx())
+        return i18n("GLX/OpenGL are not available and only OpenGL support is compiled.");
+#else
+    if (!(hasGlx()
+            || (Xcb::Extensions::self()->isRenderAvailable() && Xcb::Extensions::self()->isFixesAvailable()))) {
+        return i18n("GLX/OpenGL and XRender/XFixes are not available.");
+    }
+#endif
+    return QString();
+}
+
+bool X11StandalonePlatform::compositingPossible() const
+{
+    // first off, check whether we figured that we'll crash on detection because of a buggy driver
+    KConfigGroup gl_workaround_group(kwinApp()->config(), "Compositing");
+    const QString unsafeKey(QLatin1String("OpenGLIsUnsafe") + (kwinApp()->isX11MultiHead() ? QString::number(kwinApp()->x11ScreenNumber()) : QString()));
+    if (gl_workaround_group.readEntry("Backend", "OpenGL") == QLatin1String("OpenGL") &&
+        gl_workaround_group.readEntry(unsafeKey, false))
+        return false;
+
+
+    if (!Xcb::Extensions::self()->isCompositeAvailable()) {
+        qCDebug(KWIN_CORE) << "No composite extension available";
+        return false;
+    }
+    if (!Xcb::Extensions::self()->isDamageAvailable()) {
+        qCDebug(KWIN_CORE) << "No damage extension available";
+        return false;
+    }
+    if (hasGlx())
+        return true;
+#ifdef KWIN_HAVE_XRENDER_COMPOSITING
+    if (Xcb::Extensions::self()->isRenderAvailable() && Xcb::Extensions::self()->isFixesAvailable())
+        return true;
+#endif
+    if (QOpenGLContext::openGLModuleType() == QOpenGLContext::LibGLES) {
+        return true;
+    } else if (qstrcmp(qgetenv("KWIN_COMPOSE"), "O2ES") == 0) {
+        return true;
+    }
+    qCDebug(KWIN_CORE) << "No OpenGL or XRender/XFixes support";
+    return false;
+}
+
+bool X11StandalonePlatform::hasGlx()
+{
+    return Xcb::Extensions::self()->hasGlx();
+}
 
 }
diff --git a/plugins/platforms/x11/standalone/x11_platform.h b/plugins/platforms/x11/standalone/x11_platform.h
index 949f804ca..dd6c71b6b 100644
--- a/plugins/platforms/x11/standalone/x11_platform.h
+++ b/plugins/platforms/x11/standalone/x11_platform.h
@@ -1,50 +1,65 @@
 /********************************************************************
  KWin - the KDE window manager
  This file is part of the KDE project.
 
 Copyright (C) 2016 Martin Gräßlin <mgraesslin@kde.org>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #ifndef KWIN_X11STANDALONE_PLATFORM_H
 #define KWIN_X11STANDALONE_PLATFORM_H
 #include "platform.h"
 
 #include <kwin_export.h>
 
 #include <QObject>
 
 namespace KWin
 {
 
 class KWIN_EXPORT X11StandalonePlatform : public Platform
 {
     Q_OBJECT
     Q_INTERFACES(KWin::Platform)
     Q_PLUGIN_METADATA(IID "org.kde.kwin.Platform" FILE "x11.json")
 public:
     X11StandalonePlatform(QObject *parent = nullptr);
     virtual ~X11StandalonePlatform();
     void init() override;
 
     Screens *createScreens(QObject *parent = nullptr) override;
     OpenGLBackend *createOpenGLBackend() override;
     Edge *createScreenEdge(ScreenEdges *parent) override;
     bool requiresCompositing() const override;
+    bool compositingPossible() const override;
+    QString compositingNotPossibleReason() const override;
+    bool openGLCompositingIsBroken() const override;
+
+private:
+    /**
+     * Tests whether GLX is supported and returns @c true
+     * in case KWin is compiled with OpenGL support and GLX
+     * is available.
+     *
+     * If KWin is compiled with OpenGL ES or without OpenGL at
+     * all, @c false is returned.
+     * @returns @c true if GLX is available, @c false otherwise and if not build with OpenGL support.
+     **/
+    static bool hasGlx();
 
 };
 
 }
 
 #endif