https://bugs.kde.org/show_bug.cgi?id=505775
Bug ID: 505775
Summary: Enabling Translucent Windows in Desktop Effects causes
flickering in Windows with Wayland
Classification: Plasma
Product: kwin
Version First 6.3.5
Reported In:
Platform: Arch Linux
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: compositing
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
SUMMARY
Severe flickering artifacts appear at the bottom edge of windows on a secondary
monitor when the “Translucency” KWin effect is enabled under Wayland with
NVIDIA GPUs. Flickering consistently occurs when Chromium-based browser windows
are tiled or partially overlapped. Disabling the Translucency effect fully
resolves the issue.
STEPS TO REPRODUCE
Use KDE Plasma session on Wayland with NVIDIA RTX 4090 and proprietary
driver.
Enable the Translucency KWin effect (enabled by default in some themes).
Use a dual-monitor setup, both at 3840x2160@240Hz, with both displays set
to 100% scale.
Open two Chromium-based browser windows and tile/snap them side-by-side on
the secondary monitor.
OBSERVED RESULT
Significant flickering artifacts appear, mostly at the bottom or
bottom-right of windows.
Flickering often reveals visual “ghosting” of the desktop background.
The issue disappears completely when the Translucency effect is disabled.
EXPECTED RESULT
No flickering or redraw artifacts should occur with standard compositing
effects like Translucency, even under NVIDIA Wayland sessions.
SOFTWARE/OS VERSIONS
Linux/KDE Plasma: CachyOS (rolling, Arch-based)
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.x
Qt Version: 6.9.1
Kernel Version: 6.15.2-3-cachyos
Graphics Platform: Wayland
GPU: NVIDIA RTX 4090
Driver Version: NVIDIA 575.64
Monitors: Dual 4K @ 240Hz (DP-1 and DP-2)
Scaling: Both monitors at 100%
Compositing Backend: OpenGL + EGL
ADDITIONAL INFORMATION
Issue is not resolved by disabling Adaptive Sync, matching refresh rates,
or unifying scale factors.
Using the KWIN_DRM_NO_AMS=1 workaround did not help and caused a black
screen at login.
Disabling the Translucency effect immediately resolves the problem,
indicating a likely bug in the compositor’s handling of translucent regions
under NVIDIA EGL on Wayland.
Not reproducible under Plasma (X11), which is stable under the same
hardware.
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