Bug 460258

Summary:	Heavy graphical glitches when letting XWayland applications scale themselves
Product:	[Plasma] kwin	Reporter:	kskot <288pat0tem>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	nate, xaver.hugl
Priority:	NOR
Version First Reported In:	5.26.0
Target Milestone:	---
Platform:	Other
OS:	Other
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Glitches in VLC menu

Description kskot 2022-10-11 17:49:40 UTC

SUMMARY
XWayland applications have heavy graphical glitches when selecting "Apply scaling themselves". 


STEPS TO REPRODUCE
1. Open Display Configuration
2. Select "Apply scaling themselves" for Legacy Applications
3. Reboot
4. Start XWayland application (tested with Signal via Flatpak and Intellij via Snap)
5. Notice the graphical glitches

OBSERVED RESULT
Graphical glitches which make the applications unusable

EXPECTED RESULT
No glitches

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.26
KDE Plasma Version: 5.26.0
KDE Frameworks Version: 5.98.0
Qt Version: 5.15.6
Kernel Version: 5.15.0-50-generic (64-bit)
Graphics Platform: Wayland
Processors: 12 × Intel® Core™ i7-10750H CPU @ 2.60GHz
Memory: 31,1 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics

ADDITIONAL INFORMATION
KDE Frameworks is still on 5.98 instead of 5.99. Is 5.99 required for this to work? Neon currently only ships 5.98.

Comment 1 Nate Graham 2022-10-12 19:53:09 UTC

With that same CPU and GPU, I don't see any graphical glitches with Discord, VLC, or Chromium.

Can you attach a screenshot of the issue?

Comment 2 kskot 2022-10-12 20:58:09 UTC

Created attachment 152754 [details]
Glitches in VLC menu

Here you can see some glitches in VLC. As soon as I move my mouse, all highlighted entries begin to flicker. 

I had to use an external camera to take the screenshot because the glitches do not show up when using Spectacle.

Comment 3 Nate Graham 2022-10-14 17:41:59 UTC

Yikes!

Comment 4 kskot 2022-10-16 22:07:28 UTC

Turns out the glitches only appear when the display is scaled to something higher than 100%. With 75% scaling or 100% scaling no bugs are present.

Comment 5 kskot 2022-10-24 22:00:37 UTC

I experienced these glitches on my notebook, which has a Intel integrated GPU and a discrete Nvidia GPU. When setting the "PRIME Profiles" in Nvidia settings to "Intel" the glitches go away. When the glitches appeared I had it on "Nvidia On-Demand". So it seems it is probably an Nvidia driver issue.

Comment 6 kskot 2023-09-12 22:08:37 UTC

Fixed by updating the nvidia driver.