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Maniphest T10016

Improve Wayland zero output handling
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Description

When no output is connected, there are problems:

  • In Drm backend final output removal is not propagated via screensQueried, seg faults.
  • Having no wl_output crashes clients.

Proposed steps:

  • Move Wayland output creation from plugins to AbstractOutput
  • Create dummy output in OutputScreens
  • Always call screensQueried

Details

Differential Revisions
D26511: [platforms/drm] Allow running without outputs
D17985: [platforms/drm] Mark outputs as disabled if we don't have any outputs
D16791: [drm] On update always emit screensQueried
D16790: Set outputs enabled in AbstractOutput
D16789: Abstract OutputDevice initialization
D16787: Abstract output dpms handling
D16786: Set mode in AbstractOutput
D16785: Handle Wayland change sets in AbstractOutput
D16783: Initialize Wayland output in AbstractOutput

Related Objects

romangg created this task.Nov 9 2018, 5:14 PM
romangg triaged this task as High priority.
davidedmundson added a subscriber: davidedmundson.Nov 9 2018, 7:48 PM

Having no wl_output crashes clients

That's a client bug then. Qt shouldn't have an issue.

romangg added a comment.Nov 9 2018, 8:13 PM
In T10016#166877, @davidedmundson wrote:

Having no wl_output crashes clients

That's a client bug then. Qt shouldn't have an issue.

Martin assumed otherwise here: https://bugs.kde.org/show_bug.cgi?id=389551

Since I experienced crashes in KDE apps and plasmashell when removing all screens, I thought his assumption is right although this would be of course somewhat an oversight in the Wayland protocol specification. You think it should be no problem?

romangg added a comment.Sep 16 2019, 10:26 AM

From other task:

In T7331#199916, @davidedmundson wrote:

But I heard different things about that.

Kwin's internal QPA now fakes having a screen if there's none. Same as the QtWayland and QtXCB QPAs.
It might be enough to close the crashing task.

romangg moved this task from Backlog to Work In Progress on the KWin board.Dec 11 2019, 12:42 PM
romangg moved this task from Work In Progress to Done on the KWin board.Jan 8 2020, 9:21 AM
romangg closed this task as Resolved.