Bug 443953

Summary:	Black screen with GLES compositing on LLVMpipe
Product:	[Plasma] kwin	Reporter:	Fabian Vogt <fabian>
Component:	platform-x11-standalone	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	grave	CC:	nate, woebbeking
Priority:	NOR	Keywords:	regression
Version First Reported In:	5.23.0
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:	https://invent.kde.org/plasma/kwin/commit/140834e75a86153e50c7551802085272cab6bff1	Version Fixed/Implemented In:	5.23.1
Sentry Crash Report:

Description Fabian Vogt 2021-10-18 09:00:31 UTC

KWin using GLES uses EGL and it requires some EGL_image extensions, which are not provided by Mesa-LLVMpipe, so compositing fails to initialize.

Before 5.23, it would fall back to XRender compositing and work properly.

With 5.23, it is unable to start compositing because XRender got removed, and so it disables compositing.

Now it however fails to disable compositing properly, and the screen stays black forever, probably because either the overlay window is not properly removed or xcb_composite_unredirect_subwindows is not called.

It works when disabling compositing explicitly, so that kwin doesn't even attempt to initialize it.

Comment 1 Vlad Zahorodnii 2021-10-18 10:30:45 UTC

Git commit 85f8a533604f9f8d8d61aea8987a82a211ea10a0 by Vlad Zahorodnii.
Committed on 18/10/2021 at 10:20.
Pushed by vladz into branch 'master'.

x11: Properly unredirect windows if compositing is not possible

Before attempting to create scenes, kwin will redirect windows but if
the opengl scene can't be created, it won't unredirect windows, which
seems to cause issues on aarch64.

M  +4    -0    src/composite.cpp

https://invent.kde.org/plasma/kwin/commit/85f8a533604f9f8d8d61aea8987a82a211ea10a0

Comment 2 Vlad Zahorodnii 2021-10-18 10:31:16 UTC

Git commit 140834e75a86153e50c7551802085272cab6bff1 by Vlad Zahorodnii.
Committed on 18/10/2021 at 10:31.
Pushed by vladz into branch 'Plasma/5.23'.

x11: Properly unredirect windows if compositing is not possible

Before attempting to create scenes, kwin will redirect windows but if
the opengl scene can't be created, it won't unredirect windows, which
seems to cause issues on aarch64.


(cherry picked from commit 85f8a533604f9f8d8d61aea8987a82a211ea10a0)

M  +4    -0    src/composite.cpp

https://invent.kde.org/plasma/kwin/commit/140834e75a86153e50c7551802085272cab6bff1

Comment 3 Andre Woebbeking 2021-10-19 16:51:29 UTC

I wonder if I've the same problem. When I login (plasma_x11) I see SUSE's light bulb forever. I've to kill KWin, disable compositing and restart KWin. Then I can work again but get many graphical artefacts.

This is on Tumbleweed, Plasma 5.23 with Intel UHD Graphics.