https://bugs.kde.org/show_bug.cgi?id=524117
--- Comment #3 from Vlad Sizykh <[email protected]> --- Thanks for the detailed investigation! I can reproduce the same glitches using the Night Light preview commands. Let me know if you need anything from my side. On Tue, Aug 11, 2026 at 5:00 PM bedo <[email protected]> wrote: > 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 reported the bug. -- You are receiving this mail because: You are watching all bug changes.
