Bug 446936

Summary:	git master - Cursor appears dark/corrupted with RDNA2 gpu under Wayland
Product:	[Plasma] kwin	Reporter:	Jon Voss <jonvoss>
Component:	core	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	nate, xaver.hugl
Priority:	NOR	Keywords:	regression
Version First Reported In:	git master
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
URL:	https://gitlab.freedesktop.org/drm/amd/-/issues/1513
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Jon Voss 2021-12-13 14:12:21 UTC

SUMMARY
Running the latest git master build of Plasma Wayland on a Radeon 6700XT, the cursor appears darker than it should be. Sort of a "corrupted" state. I believe this is related to the gamma changes in MR https://invent.kde.org/plasma/kwin/-/merge_requests/1335 - using the full gamma ramp from the kernel driver causes an issue with the coloring of the cursor. This happens under X11 as well, and not just with Plasma. Under X11, the issue can be mitigated by using the modesetting driver and disabling the UseGammaLUT option.

It looks like this is an issue with amdgpu, there has been an open issue over for quite a while:
https://gitlab.freedesktop.org/drm/amd/-/issues/1513

I would grab a screenshot, but it doesn't show up well. The best example is in the issue above.
Submitting this for awareness and tracking.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
Kernel Version: 5.15.7-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800X 8-Core Processor
Memory: 15.6 GiB of RAM
Graphics Processor: AMD Radeon RX 6700 XT

Comment 1 Jon Voss 2021-12-13 15:38:21 UTC

As suspected, reverting these commits in kwin made the cursor appear normal again:

3fb14035 backends/drm: only use atomic gamma size with AMS
4206046f Re-enable proper gamma ramps with AMS

I mispoke on the MR - the correct MR is:
https://invent.kde.org/plasma/kwin/-/merge_requests/1472

Comment 2 Zamundaaa 2021-12-20 10:58:21 UTC

If really necessary we can turn off proper gamma once again... but I'd rather not hide driver breakage all the time, especially not if it reduces color accuracy. This should be fixed upstream