Bug 461409

Summary:	Mouse cursor distorted when hovering over window title
Product:	[Plasma] kwin	Reporter:	Will <kdebugs>
Component:	decorations	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REPORTED ---
Severity:	minor	CC:	kdebugs, nate, xaver.hugl
Priority:	NOR	Keywords:	wayland-only
Version First Reported In:	5.26.2
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Will 2022-11-04 11:03:27 UTC

SUMMARY

My mouse cursor (using the default theme, haven't tried another one yet) has some visible distortion when hovering over the title bar of a window. 

STEPS TO REPRODUCE
1. Move mouse between window border and window contents 

OBSERVED RESULT
The cursor acquires some visual glitchiness when moving to the title bar, and going back to normal when moving to the window contents.

EXPECTED RESULT
The cursor should look the same.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Linux 6.0.6
KDE Plasma Version: 5.26.2
KDE Frameworks Version: 5.99.0
Qt Version: 5.15.7

ADDITIONAL INFORMATION
I'm using Wayland with the open source AMD graphics driver. I have multiple monitors, all scaled to 125%. XWayland doesn't seem to matter, even Wayland-native applications will do this. Interestingly, Firefox's tab bar doesn't do it (I've unchecked the "title bar" setting).

I've uploaded a video because a screenshot that includes the mouse cursor doesn't show any difference I could see: https://youtu.be/Rks5lSzwGDo

Comment 1 Nate Graham 2022-11-04 17:58:54 UTC

Very likely a graphics driver issue.

If you set KWIN_DRM_NO_AMS=1 in /etc/environment and reboot, does the issue go away?

Comment 2 Will 2022-11-04 23:24:46 UTC

(In reply to Nate Graham from comment #1)
> Very likely a graphics driver issue.
> 
> If you set KWIN_DRM_NO_AMS=1 in /etc/environment and reboot, does the issue
> go away?

Thanks for the quick reply! It doesn't seem as bad, but it's still present.

Comment 3 Nate Graham 2022-11-07 18:25:27 UTC

OK cool, now how about these?

KWIN_DRM_USE_MODIFIERS=0
KWIN_DRM_PREFER_COLOR_DEPTH=24

Can you test them one at a time?

Comment 4 Will 2022-11-09 11:33:55 UTC

Hi Nate, sorry for the delay, it's been a busy couple of days. Thanks for the suggestions - I tried them both, neither made a difference at all, not even the small improvement I saw with `KWIN_DRM_NO_AMS=1`.

Comment 5 Nate Graham 2022-11-09 19:42:49 UTC

Ok, thanks!