https://bugs.kde.org/show_bug.cgi?id=527668
[email protected] changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #8 from [email protected] --- Bisected this on my machine, and I think the culprit is 01222b41 (backends/drm: disable color pipelines for 6.8). Stock 6.8.1 with KWIN_DRM_USE_COLOR_PIPELINE=1 is completely smooth for me. Without it, I get the same stutter as everyone else here as soon as both screens are on. What I tried, all on the same system: - 6.8.1 stock: stutters - 6.8.1 with KWIN_WAYLAND_SUPPORT_COMMIT_TIMING_V1=0: a bit better, still stutters - 6.8.1 with the repaint/renderloop/cursor changes from this release reverted: still stutters - 6.8.0 source: smooth - 6.8.1 stock + KWIN_DRM_USE_COLOR_PIPELINE=1: smooth Dropping the second screen from 180 Hz to 120 Hz didn't help, and unloading blur didn't change anything either. The cursor is the easiest place to see it: smooth over the desktop, noticeably choppy over a client window on the 240 Hz screen. That lines up with comment 1, which mentioned screen flashes on 6.8.0 that went away in 6.8.1 when this started. I see the same trade-off: with KWIN_DRM_USE_COLOR_PIPELINE=1 the stutter is gone, but the washed-out flashes from bug 525839 come back, a pale white overlay on fullscreen content whenever something moves on screen. So on 6.8.1 it's either the stutter or the flashes, and disabling color pipelines to work around bug 525839 looks like what's causing this one. Master still defaults to color pipelines on, so I'd guess 6.9 isn't affected by the stutter, but it presumably has the flashes instead. Both my screens have ICC profiles set, which might be relevant given the change. Setup: NixOS, KWin 6.8.1, Qt 6.12.0, Mesa 26.2.5, kernel 7.3.0 (CachyOS), 7900 XTX. DP-1: 3840x2160 @ 240 Hz, scale 1.5, VRR automatic DP-2: 2560x1440 @ 180 Hz, scale 1, VRR automatic allowTearing: true Support information attached. -- You are receiving this mail because: You are watching all bug changes.
