https://bugs.kde.org/show_bug.cgi?id=527664
Bug ID: 527664
Summary: [Wayland] Severe flicker/tearing on external display
(hybrid GPU, NVIDIA output) — regression in 6.8, fixed
by KWIN_DRM_NO_TRIPLE_BUFFERING=1
Classification: Plasma
Product: kwin
Version First 6.8.1
Reported In:
Platform: CachyOS
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: compositing
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Environment:
- KWin 6.8.1 (regression began with 6.7.5 -> 6.8.0), Wayland session
- ASUS TUF Gaming FX505GD: Intel UHD 630 (rendering) + NVIDIA GTX 1050
(Pascal), driver 580.178.04
- External monitor Samsung S22E450, 1920x1080@60 via HDMI (HDMI output wired to
the NVIDIA GPU)
- Kernel 7.3.0-cachyos (also reproduced on hardened / rt-bore / lts kernels)
Symptoms:
- External display only: strong strobing flicker and tearing, triggered by
window movement and scrolling. Internal panel is clean; screenshots do not show
the artifact.
Verified not at fault:
- New HDMI cable, monitor factory reset, driver reinstall (DKMS rebuild),
kscreen config reset — no change. Monitor works fine with another laptop.
Booting an older CachyOS live ISO (KWin 6.7 era) is completely clean.
Workaround:
- KWIN_DRM_NO_TRIPLE_BUFFERING=1 completely eliminates the problem. Without it
the artifact is present on every session. Journal occasionally shows "Atomic
commit failed: EACCESS".
Suspected cause: 6.8 enabling triple buffering for NVIDIA interacts badly with
the cross-GPU (Intel render -> NVIDIA output) presentation path.
--
You are receiving this mail because:
You are watching all bug changes.
