Differential D10747 Diff 60360 src/client/protocols/linux-dmabuf-unstable-v1.xml

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src/client/protocols/linux-dmabuf-unstable-v1.xml

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		1		<?xml version="1.0" encoding="UTF-8"?>
		2		<protocol name="linux_dmabuf_unstable_v1">
		3
		4		<copyright>
		5		Copyright © 2014, 2015 Collabora, Ltd.
		6
		7		Permission is hereby granted, free of charge, to any person obtaining a
		8		copy of this software and associated documentation files (the "Software"),
		9		to deal in the Software without restriction, including without limitation
		10		the rights to use, copy, modify, merge, publish, distribute, sublicense,
		11		and/or sell copies of the Software, and to permit persons to whom the
		12		Software is furnished to do so, subject to the following conditions:
		13
		14		The above copyright notice and this permission notice (including the next
		15		paragraph) shall be included in all copies or substantial portions of the
		16		Software.
		17
		18		THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
		19		IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
		20		FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
		21		THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
		22		LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
		23		FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
		24		DEALINGS IN THE SOFTWARE.
		25		</copyright>
		26
		27		<interface name="zwp_linux_dmabuf_v1" version="3">
		28		<description summary="factory for creating dmabuf-based wl_buffers">
		29		Following the interfaces from:
		30		https://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_import.txt
		31		and the Linux DRM sub-system's AddFb2 ioctl.
		32
		33		This interface offers ways to create generic dmabuf-based
		34		wl_buffers. Immediately after a client binds to this interface,
		35		the set of supported formats and format modifiers is sent with
		36		'format' and 'modifier' events.
		37
		38		The following are required from clients:
		39
		40		- Clients must ensure that either all data in the dma-buf is
		41		coherent for all subsequent read access or that coherency is
		42		correctly handled by the underlying kernel-side dma-buf
		43		implementation.
		44
		45		- Don't make any more attachments after sending the buffer to the
		46		compositor. Making more attachments later increases the risk of
		47		the compositor not being able to use (re-import) an existing
		48		dmabuf-based wl_buffer.
		49
		50		The underlying graphics stack must ensure the following:
		51
		52		- The dmabuf file descriptors relayed to the server will stay valid
		53		for the whole lifetime of the wl_buffer. This means the server may
		54		at any time use those fds to import the dmabuf into any kernel
		55		sub-system that might accept it.
		56
		57		To create a wl_buffer from one or more dmabufs, a client creates a
		58		zwp_linux_dmabuf_params_v1 object with a zwp_linux_dmabuf_v1.create_params
		59		request. All planes required by the intended format are added with
		60		the 'add' request. Finally, a 'create' or 'create_immed' request is
		61		issued, which has the following outcome depending on the import success.
		62
		63		The 'create' request,
		64		- on success, triggers a 'created' event which provides the final
		65		wl_buffer to the client.
		66		- on failure, triggers a 'failed' event to convey that the server
		67		cannot use the dmabufs received from the client.
		68
		69		For the 'create_immed' request,
		70		- on success, the server immediately imports the added dmabufs to
		71		create a wl_buffer. No event is sent from the server in this case.
		72		- on failure, the server can choose to either:
		73		- terminate the client by raising a fatal error.
		74		- mark the wl_buffer as failed, and send a 'failed' event to the
		75		client. If the client uses a failed wl_buffer as an argument to any
		76		request, the behaviour is compositor implementation-defined.
		77
		78		Warning! The protocol described in this file is experimental and
		79		backward incompatible changes may be made. Backward compatible changes
		80		may be added together with the corresponding interface version bump.
		81		Backward incompatible changes are done by bumping the version number in
		82		the protocol and interface names and resetting the interface version.
		83		Once the protocol is to be declared stable, the 'z' prefix and the
		84		version number in the protocol and interface names are removed and the
		85		interface version number is reset.
		86		</description>
		87
		88		<request name="destroy" type="destructor">
		89		<description summary="unbind the factory">
		90		Objects created through this interface, especially wl_buffers, will
		91		remain valid.
		92		</description>
		93		</request>
		94
		95		<request name="create_params">
		96		<description summary="create a temporary object for buffer parameters">
		97		This temporary object is used to collect multiple dmabuf handles into
		98		a single batch to create a wl_buffer. It can only be used once and
		99		should be destroyed after a 'created' or 'failed' event has been
		100		received.
		101		</description>
		102		<arg name="params_id" type="new_id" interface="zwp_linux_buffer_params_v1"
		103		summary="the new temporary"/>
		104		</request>
		105
		106		<event name="format">
		107		<description summary="supported buffer format">
		108		This event advertises one buffer format that the server supports.
		109		All the supported formats are advertised once when the client
		110		binds to this interface. A roundtrip after binding guarantees
		111		that the client has received all supported formats.
		112
		113		For the definition of the format codes, see the
		114		zwp_linux_buffer_params_v1::create request.
		115
		116		Warning: the 'format' event is likely to be deprecated and replaced
		117		with the 'modifier' event introduced in zwp_linux_dmabuf_v1
		118		version 3, described below. Please refrain from using the information
		119		received from this event.
		120		</description>
		121		<arg name="format" type="uint" summary="DRM_FORMAT code"/>
		122		</event>
		123
		124		<event name="modifier" since="3">
		125		<description summary="supported buffer format modifier">
		126		This event advertises the formats that the server supports, along with
		127		the modifiers supported for each format. All the supported modifiers
		128		for all the supported formats are advertised once when the client
		129		binds to this interface. A roundtrip after binding guarantees that
		130		the client has received all supported format-modifier pairs.
		131
		132		For the definition of the format and modifier codes, see the
		133		zwp_linux_buffer_params_v1::create request.
		134		</description>
		135		<arg name="format" type="uint" summary="DRM_FORMAT code"/>
		136		<arg name="modifier_hi" type="uint"
		137		summary="high 32 bits of layout modifier"/>
		138		<arg name="modifier_lo" type="uint"
		139		summary="low 32 bits of layout modifier"/>
		140		</event>
		141		</interface>
		142
		143		<interface name="zwp_linux_buffer_params_v1" version="3">
		144		<description summary="parameters for creating a dmabuf-based wl_buffer">
		145		This temporary object is a collection of dmabufs and other
		146		parameters that together form a single logical buffer. The temporary
		147		object may eventually create one wl_buffer unless cancelled by
		148		destroying it before requesting 'create'.
		149
		150		Single-planar formats only require one dmabuf, however
		151		multi-planar formats may require more than one dmabuf. For all
		152		formats, an 'add' request must be called once per plane (even if the
		153		underlying dmabuf fd is identical).
		154
		155		You must use consecutive plane indices ('plane_idx' argument for 'add')
		156		from zero to the number of planes used by the drm_fourcc format code.
		157		All planes required by the format must be given exactly once, but can
		158		be given in any order. Each plane index can be set only once.
		159		</description>
		160
		161		<enum name="error">
		162		<entry name="already_used" value="0"
		163		summary="the dmabuf_batch object has already been used to create a wl_buffer"/>
		164		<entry name="plane_idx" value="1"
		165		summary="plane index out of bounds"/>
		166		<entry name="plane_set" value="2"
		167		summary="the plane index was already set"/>
		168		<entry name="incomplete" value="3"
		169		summary="missing or too many planes to create a buffer"/>
		170		<entry name="invalid_format" value="4"
		171		summary="format not supported"/>
		172		<entry name="invalid_dimensions" value="5"
		173		summary="invalid width or height"/>
		174		<entry name="out_of_bounds" value="6"
		175		summary="offset + stride * height goes out of dmabuf bounds"/>
		176		<entry name="invalid_wl_buffer" value="7"
		177		summary="invalid wl_buffer resulted from importing dmabufs via
		178		the create_immed request on given buffer_params"/>
		179		</enum>
		180
		181		<request name="destroy" type="destructor">
		182		<description summary="delete this object, used or not">
		183		Cleans up the temporary data sent to the server for dmabuf-based
		184		wl_buffer creation.
		185		</description>
		186		</request>
		187
		188		<request name="add">
		189		<description summary="add a dmabuf to the temporary set">
		190		This request adds one dmabuf to the set in this
		191		zwp_linux_buffer_params_v1.
		192
		193		The 64-bit unsigned value combined from modifier_hi and modifier_lo
		194		is the dmabuf layout modifier. DRM AddFB2 ioctl calls this the
		195		fb modifier, which is defined in drm_mode.h of Linux UAPI.
		196		This is an opaque token. Drivers use this token to express tiling,
		197		compression, etc. driver-specific modifications to the base format
		198		defined by the DRM fourcc code.
		199
		200		This request raises the PLANE_IDX error if plane_idx is too large.
		201		The error PLANE_SET is raised if attempting to set a plane that
		202		was already set.
		203		</description>
		204		<arg name="fd" type="fd" summary="dmabuf fd"/>
		205		<arg name="plane_idx" type="uint" summary="plane index"/>
		206		<arg name="offset" type="uint" summary="offset in bytes"/>
		207		<arg name="stride" type="uint" summary="stride in bytes"/>
		208		<arg name="modifier_hi" type="uint"
		209		summary="high 32 bits of layout modifier"/>
		210		<arg name="modifier_lo" type="uint"
		211		summary="low 32 bits of layout modifier"/>
		212		</request>
		213
		214		<enum name="flags">
		215		<entry name="y_invert" value="1" summary="contents are y-inverted"/>
		216		<entry name="interlaced" value="2" summary="content is interlaced"/>
		217		<entry name="bottom_first" value="4" summary="bottom field first"/>
		218		</enum>
		219
		220		<request name="create">
		221		<description summary="create a wl_buffer from the given dmabufs">
		222		This asks for creation of a wl_buffer from the added dmabuf
		223		buffers. The wl_buffer is not created immediately but returned via
		224		the 'created' event if the dmabuf sharing succeeds. The sharing
		225		may fail at runtime for reasons a client cannot predict, in
		226		which case the 'failed' event is triggered.
		227
		228		The 'format' argument is a DRM_FORMAT code, as defined by the
		229		libdrm's drm_fourcc.h. The Linux kernel's DRM sub-system is the
		230		authoritative source on how the format codes should work.
		231
		232		The 'flags' is a bitfield of the flags defined in enum "flags".
		233		'y_invert' means the that the image needs to be y-flipped.
		234
		235		Flag 'interlaced' means that the frame in the buffer is not
		236		progressive as usual, but interlaced. An interlaced buffer as
		237		supported here must always contain both top and bottom fields.
		238		The top field always begins on the first pixel row. The temporal
		239		ordering between the two fields is top field first, unless
		240		'bottom_first' is specified. It is undefined whether 'bottom_first'
		241		is ignored if 'interlaced' is not set.
		242
		243		This protocol does not convey any information about field rate,
		244		duration, or timing, other than the relative ordering between the
		245		two fields in one buffer. A compositor may have to estimate the
		246		intended field rate from the incoming buffer rate. It is undefined
		247		whether the time of receiving wl_surface.commit with a new buffer
		248		attached, applying the wl_surface state, wl_surface.frame callback
		249		trigger, presentation, or any other point in the compositor cycle
		250		is used to measure the frame or field times. There is no support
		251		for detecting missed or late frames/fields/buffers either, and
		252		there is no support whatsoever for cooperating with interlaced
		253		compositor output.
		254
		255		The composited image quality resulting from the use of interlaced
		256		buffers is explicitly undefined. A compositor may use elaborate
		257		hardware features or software to deinterlace and create progressive
		258		output frames from a sequence of interlaced input buffers, or it
		259		may produce substandard image quality. However, compositors that
		260		cannot guarantee reasonable image quality in all cases are recommended
		261		to just reject all interlaced buffers.
		262
		263		Any argument errors, including non-positive width or height,
		264		mismatch between the number of planes and the format, bad
		265		format, bad offset or stride, may be indicated by fatal protocol
		266		errors: INCOMPLETE, INVALID_FORMAT, INVALID_DIMENSIONS,
		267		OUT_OF_BOUNDS.
		268
		269		Dmabuf import errors in the server that are not obvious client
		270		bugs are returned via the 'failed' event as non-fatal. This
		271		allows attempting dmabuf sharing and falling back in the client
		272		if it fails.
		273
		274		This request can be sent only once in the object's lifetime, after
		275		which the only legal request is destroy. This object should be
		276		destroyed after issuing a 'create' request. Attempting to use this
		277		object after issuing 'create' raises ALREADY_USED protocol error.
		278
		279		It is not mandatory to issue 'create'. If a client wants to
		280		cancel the buffer creation, it can just destroy this object.
		281		</description>
		282		<arg name="width" type="int" summary="base plane width in pixels"/>
		283		<arg name="height" type="int" summary="base plane height in pixels"/>
		284		<arg name="format" type="uint" summary="DRM_FORMAT code"/>
		285		<arg name="flags" type="uint" summary="see enum flags"/>
		286		</request>
		287
		288		<event name="created">
		289		<description summary="buffer creation succeeded">
		290		This event indicates that the attempted buffer creation was
		291		successful. It provides the new wl_buffer referencing the dmabuf(s).
		292
		293		Upon receiving this event, the client should destroy the
		294		zlinux_dmabuf_params object.
		295		</description>
		296		<arg name="buffer" type="new_id" interface="wl_buffer"
		297		summary="the newly created wl_buffer"/>
		298		</event>
		299
		300		<event name="failed">
		301		<description summary="buffer creation failed">
		302		This event indicates that the attempted buffer creation has
		303		failed. It usually means that one of the dmabuf constraints
		304		has not been fulfilled.
		305
		306		Upon receiving this event, the client should destroy the
		307		zlinux_buffer_params object.
		308		</description>
		309		</event>
		310
		311		<request name="create_immed" since="2">
		312		<description summary="immediately create a wl_buffer from the given
		313		dmabufs">
		314		This asks for immediate creation of a wl_buffer by importing the
		315		added dmabufs.
		316
		317		In case of import success, no event is sent from the server, and the
		318		wl_buffer is ready to be used by the client.
		319
		320		Upon import failure, either of the following may happen, as seen fit
		321		by the implementation:
		322		- the client is terminated with one of the following fatal protocol
		323		errors:
		324		- INCOMPLETE, INVALID_FORMAT, INVALID_DIMENSIONS, OUT_OF_BOUNDS,
		325		in case of argument errors such as mismatch between the number
		326		of planes and the format, bad format, non-positive width or
		327		height, or bad offset or stride.
		328		- INVALID_WL_BUFFER, in case the cause for failure is unknown or
		329		plaform specific.
		330		- the server creates an invalid wl_buffer, marks it as failed and
		331		sends a 'failed' event to the client. The result of using this
		332		invalid wl_buffer as an argument in any request by the client is
		333		defined by the compositor implementation.
		334
		335		This takes the same arguments as a 'create' request, and obeys the
		336		same restrictions.
		337		</description>
		338		<arg name="buffer_id" type="new_id" interface="wl_buffer"
		339		summary="id for the newly created wl_buffer"/>
		340		<arg name="width" type="int" summary="base plane width in pixels"/>
		341		<arg name="height" type="int" summary="base plane height in pixels"/>
		342		<arg name="format" type="uint" summary="DRM_FORMAT code"/>
		343		<arg name="flags" type="uint" summary="see enum flags"/>
		344		</request>
		345
		346		</interface>
		347
		348		</protocol>