Bug 488812

Summary:	Intel i915 (ARC A770): enabling HDR results in corrupted screen
Product:	[Plasma] kwin	Reporter:	Nowa Ammerlaan <nowa>
Component:	colour-management	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	nate, xaver.hugl
Priority:	NOR
Version First Reported In:	6.1.0
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
See Also:	https://gitlab.freedesktop.org/mesa/mesa/-/issues/11460
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	log format and modifier of the shadow buffer

Description Nowa Ammerlaan 2024-06-20 18:29:29 UTC

SUMMARY

Enabling HDR for my MSI Optix MAG342CQR using an Intel ARC A770 card results in a corrupted display (see attachments).

Note, KWIN_DRM_ALLOW_INTEL_COLORSPACE=1 is in the environment, to make this setting show up at all.

Considering that the state of HDR on Intel platforms is experimental this may very well be an i915 bug. But I am reporting it here because it worked mostly okay in kwin 6.0, but is now no longer working at all in 6.1.


STEPS TO REPRODUCE
1.  add KWIN_DRM_ALLOW_INTEL_COLORSPACE=1 to system wide environment
2.  restart
3.  enable HDR in display settings

OBSERVED RESULT

See attachments

EXPECTED RESULT

No corrupted display


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Gentoo Linux 
KDE Plasma Version: 6.1.0
KDE Frameworks Version: 6.3.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION

Please let me know if and how I can provide i915/kwin debug logs that may be helpful.

Comment 1 Nowa Ammerlaan 2024-06-20 18:31:50 UTC

Photos exceed file size limit, so here's a google drive link instead: https://drive.google.com/file/d/1wSD4oq04pddjrKf3r-Byat96LMuEb8DN/view?usp=sharing

Comment 2 Zamundaaa 2024-06-20 23:28:25 UTC

KWin now uses 16 bit floating point dmabufs instead of an opengl texture for compositing, which will be the cause of this issue.
RadeonSi doesn't handle them well either (https://gitlab.freedesktop.org/mesa/mesa/-/issues/10875), I assume Intel also just has problems with the used modifier on some hardware (it works fine on all tested Intel integrated GPUs so far).

If I provide a patch that prints the used format + modifier, would you apply that and make a bug report for Mesa with that information? I'll expand the workaround we have in place for AMD to Intel, but we really need this fixed in the drivers.

Comment 3 Nowa Ammerlaan 2024-06-21 08:45:10 UTC

> If I provide a patch that prints the used format + modifier, would you apply that and make a bug report for Mesa with that information? I'll expand the workaround we have in place for AMD to Intel, but we really need this fixed in the drivers.

Sure, no problem, happy to help!

Comment 4 Nowa Ammerlaan 2024-07-04 08:31:06 UTC

Today I gave the new Xe driver a try, and found that with this kernel driver I have the same HDR issue. But I guess that makes sense if the issue is in the mesa driver.

Comment 5 Zamundaaa 2024-07-04 14:44:59 UTC

Created attachment 171374 [details]
log format and modifier of the shadow buffer

Okay, here's the patch to get the format information

Comment 6 Nowa Ammerlaan 2024-07-04 16:03:36 UTC

Thanks, applied, and reported a new bug for mesa: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11460