Bug 489229

Summary:	Broken rendering with OpenGL compositing on i915
Product:	[Plasma] plasmashell	Reporter:	rachid
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	ballogyor, kde, nate, sam, xaver.hugl
Priority:	NOR
Version First Reported In:	6.1.1
Target Milestone:	1.0
Platform:	Gentoo Packages
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=482868 https://bugreports.qt.io/browse/QTBUG-126706
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description rachid 2024-06-26 12:42:18 UTC

***
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***

SUMMARY
On older video card hardware (i915) there is some broken rendering with OpenGL composting. 
In journalctl I see the following information:

Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to link shader program: error: Exceeded max ALU instructions (106/64)
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to build graphics pipeline state
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to link shader program: error: Exceeded max ALU instructions (106/64)
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to build graphics pipeline state
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to link shader program: error: Exceeded max ALU instructions (106/64)
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to build graphics pipeline state
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to link shader program: error: Exceeded max ALU instructions (106/64)
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to build graphics pipeline state
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to link shader program: error: Exceeded max ALU instructions (106/64)
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to build graphics pipeline state
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to link shader program: error: Exceeded max ALU instructions (106/64)
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to build graphics pipeline state
Jun 26 13:12:39 mrichan plasmashell[1424]: Failed to link shader program: error: Exceeded max ALU instructions (106/64)
Jun 26 13:15:13 mrichan systemsettings[1774]: Failed to link shader program: error: Exceeded max ALU instructions (77/64)
Jun 26 13:15:13 mrichan systemsettings[1774]: Failed to build graphics pipeline state
Jun 26 13:15:13 mrichan systemsettings[1774]: Failed to link shader program: error: Exceeded max ALU instructions (77/64)
Jun 26 13:15:13 mrichan systemsettings[1774]: Failed to build graphics pipeline state



STEPS TO REPRODUCE
1. Install KDE 6.1.1 (or older version) on hardware with video card i915
2. Check the logs 

OBSERVED RESULT
Issues with graphics rendering.
Also separate issue with login screen SDDM without text. I have created separate bug report: https://github.com/sddm/sddm/issues/1958

EXPECTED RESULT
No rendering issues 

SOFTWARE/OS VERSIONS 
Linux/KDE Plasma: Gentoo
(available in About System)
KDE Plasma Version: 6.1.1
KDE Frameworks Version: 6.3.0 
Qt Version: 6.7.1

ADDITIONAL INFORMATION

Comment 1 Zamundaaa 2024-06-26 13:30:23 UTC

Please attach the output of wayland-info. If KWin falls back to llvmpipe or QPainter, apps should be doing the same

Comment 2 rachid 2024-06-26 14:08:27 UTC

(In reply to Zamundaaa from comment #1)
> Please attach the output of wayland-info. If KWin falls back to llvmpipe or
> QPainter, apps should be doing the same

Currently i am using X11 and not wayland.
wayland-info
failed to create display: No such file or directory

Comment 3 Zamundaaa 2024-06-26 14:11:50 UTC

ah. Not sure we can do anything about this then; maybe Qt needs a similar check as KWin now has

Comment 4 Nate Graham 2024-06-26 16:29:29 UTC

Yeah.

Comment 5 rachid 2024-06-26 19:35:25 UTC

Is this reported to QT?

Comment 6 Balló György 2024-07-13 09:55:10 UTC

I reported this to Qt developers here:
https://bugreports.qt.io/browse/QTBUG-126962

The workaround is to specify the environment variable 'QT_QUICK_BACKEND=software' manually.

Unfortunately it triggers another bug that taskbar icons are moving to the left:
https://bugs.kde.org/show_bug.cgi?id=482669

Which is also reported to Qt developers:
https://bugreports.qt.io/browse/QTBUG-123799

Even if these issues would be solved, the Wayland session have one more bug: it crashes all the time when I press Alt-Tab
https://bugs.kde.org/show_bug.cgi?id=482663

And the mouse pointer is also broken, not rendered correctly under Wayland with the QPainter backend.

So there there are multiple things need to be fixed to make it possible to use KDE Plasma on this hardware.