https://bugs.kde.org/show_bug.cgi?id=524117

bedo <[email protected]> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[email protected]

--- Comment #2 from bedo <[email protected]> ---
I'm getting this too and have the same GPU, but I'm running two DisplayPort
monitors.

Arch Linux
AMD Radeon RX 6600 (Navi 23)
Two DisplayPort monitors, both 1920x1080 @ 60Hz
Plasma 6.7.4, Frameworks 6.28.0, Qt 6.11.1, Wayland
Mesa 26.1.6

The symptoms look the same as yours. Horizontal strips of glitchy pixels that
only show up while the transition is happening, and they vanish the moment it
finishes. A couple of extra details from my end that might help:

- The strips turn up at random vertical positions and the widths vary a lot.
It's not a fixed region of the screen.
- With two monitors each screen glitches independently. One can glitch near the
top while the other glitches near the bottom at the same time.
- Nothing gets logged at all. No kernel messages, no KWin output, no GPU
resets.

It also happens at login a lot too.

Simple way I've found to trigger it is a night light preview, which doesn't
involve DDC or brightness at all:

  qdbus6 org.kde.KWin /org/kde/KWin/NightLight org.kde.KWin.NightLight.preview
2000
  sleep 3
  qdbus6 org.kde.KWin /org/kde/KWin/NightLight
org.kde.KWin.NightLight.stopPreview

That glitches reliably here. Since there's no DDC/AUX traffic and no brightness
change involved, it seems the colour temperature transition on its own is
enough to set it off. So it might not be specific to brightness or monitor
controls.

I spent a while ruling out the kernel, and I'm fairly confident it isn't
involved. It reproduces identically on:
- linux 6.18.43-lts (stock Arch)
- linux 7.1.6.arch1, locally patched (reverted ac11060c6d49 for an unrelated
regression)

Things I tried that made no major difference:
  - amdgpu.damageclips=0
  - KWIN_DRM_NO_DIRECT_SCANOUT=1
  - KWIN_DRM_USE_MODIFIERS=0
  - KWIN_DRM_DISABLE_TRIPLE_BUFFERING=1

I made a script to reproduce before I found the this night light one. It runs
two things at once:
1. A repaint load - KDE OSD popups via org.kde.osdService.volumeChanged at
roughly 12/sec, plus notifications
2. Brightness changes through org.kde.ScreenBrightness.Display.SetBrightness,
the same call the taskbar widget makes

Glitched around 50-85% of brightness events, slightly worse when there are
windows open on the screen.
OSD repaints and DDC brightness writes alone gave me nothing. Only the two
together.
Happy to share the script, test patches, or grab whatever debug output would be
useful.

-- 
You are receiving this mail because:
You are watching all bug changes.

Reply via email to