https://bugs.kde.org/show_bug.cgi?id=527668
--- Comment #10 from [email protected] --- (In reply to me from comment #8) > 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. Update: cherry-picking 8c5bd6e6 (backends/drm: disable post-blend offloading if color pipelines aren't supported, bug 527628) onto 6.8.1 fixes it for me, without any environment variables and with color pipelines left at the 6.8.1 default. So this is probably the same issue as 527628 and should be fixed in 6.8.2. -- You are receiving this mail because: You are watching all bug changes.
