Bug 465891 - Square artifacts following cursor on some UI elements
Summary: Square artifacts following cursor on some UI elements
Status: REOPENED
Alias: None
Product: kwin
Classification: Plasma
Component: compositing (show other bugs)
Version: 5.27.0
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-02-17 06:10 UTC by Evan
Modified: 2024-02-10 04:57 UTC (History)
7 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
square artifacts (963.22 KB, video/mp4)
2023-02-17 06:10 UTC, Evan
Details

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Description Evan 2023-02-17 06:10:31 UTC
Created attachment 156344 [details]
square artifacts

SUMMARY
Square artifacts follow cursor. Seems inconsistent, sometimes it appears on the panels of none, one, or both of my monitors. Also appears on some other applications like dolphin emulator and mpv.

I think it's a new issue on 5.27.


STEPS TO REPRODUCE
1. hover over panel with cursor

OBSERVED RESULT
squares appear

EXPECTED RESULT
no squares

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux
(available in About System)
KDE Plasma Version: 5.27.0
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
GPU: AMD 7900XTX (mesa-git 23.1)
Comment 1 Evan 2023-02-17 06:44:44 UTC
Forgot to mention this is on wayland
Comment 2 Vlad Zahorodnii 2023-02-17 10:08:25 UTC

*** This bug has been marked as a duplicate of bug 465158 ***
Comment 3 Evan 2023-08-03 15:52:27 UTC
This was not fixed by https://bugs.kde.org/show_bug.cgi?id=465158 so I am reopening this bug.

Upgraded to 5.27.7 and these square artifacts are still appearing with blur desktop effect enabled. The artifact has the color of the desktop wallpaper behind it.

Linux: Arch Linux
KDE Plasma Version: 5.27.7 (wayland)
KDE Frameworks Version: 5.108.0
Qt Version: 5.15.10
GPU: AMD 7900XTX (mesa-git 23.3)
Display scaling: 150%
Comment 4 Hector Martin 2023-09-04 10:47:05 UTC
Interestingly, it looks like this one isn't specifically about blur (which got fixed recently). This happens with blur disabled too, if you kill plasmashell.

Steps to reproduce:
- Set scale to 150% (or anything non integer)
- Open some apps (e.g. konsole, systemsettings)
- killall plasmashell
- (optional) `swaybg -o '*' -i /usr/share/backgrounds/default.png` (or whatever image) to put up a background (makes the problem more obvious)
- Move the mouse and windows around (force software cursors to make it more obvious if your driver supports hardware cursors)

You'll see black single pixel trails around the cursor and window edges on the swaybg wallpaper and some window contents, but not all. E.g. the glitches seem to appear on most of the Konsole window, but on System Settings only the window decorations are affected. This happens with the blur effect completely disabled.

AIUI the blur glitch was about the blurring itself being computed wrong. This one looks like a different problem, related to dirty rectangle/redraw tracking.

KDE Plasma Version: 5.27.7 (wayland)
Comment 5 Hector Martin 2023-09-04 10:49:40 UTC
Adding Vlad to Cc since he might know more about what's going on, given his involvement with Bug 465158 and Bug 455526