https://bugs.kde.org/show_bug.cgi?id=516197
Bug ID: 516197
Summary: Display Flickering/Artifacts on Nvidia GPUs at
High-Resolution/High-Refresh-Rate (DSC) Configurations
Classification: Plasma
Product: plasmashell
Version First 6.5.5
Reported In:
Platform: Arch Linux
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: general
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected]
Target Milestone: 1.0
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SUMMARY
KDE exhibits persistent display flickering and visual artifacts when using
Nvidia drivers with monitors that require Display Stream Compression (DSC),
e.g. 4K@240Hz, 2K@360Hz, etc, via DP 1.4 or HDMI 2.1. The issue shows as
corrupted frames flashing through in the bottom-right region of the screen,
often triggered by mouse movement or window interaction.
I'm not very familiar with graphics drivers or piplelines, but the issue seems
to be fixed by Hyprland's compositor, which I think has a failsafe to ensure
the GPU has fully finished rendering before sending a frame to be displayed.
KDE/KWin has no equivalent mitigation.
Nvidia is tracking the underlying driver issue internally #4676203, and has
been made aware repeatedly over the past year, but it's unclear when a fix is
set to be released. More info from an Nvidia forum can be found at
https://forums.developer.nvidia.com/t/displayport-dsc-4k-240hz-flickering-artifacts/294490
, and specifically a post mentioning the hyprland fix is at
https://forums.developer.nvidia.com/t/displayport-dsc-4k-240hz-flickering-artifacts/294490/49
STEPS TO REPRODUCE
1. Install KDE Plasma 6.x with Wayland
2. Connect a 4K@240Hz / 2K@360Hz monitor to an Nvidia RTX GPU via DP 1.4 or
HDMI 2.1 using DSC
3. Set the monitor to its max Resolution/Refresh rate combo in settings
4. Move the mouse cursor around the screen, or open a browser
(Firefox/Chromium) and hover over the taskbar. I found specifically that steam
store pages seem to more consistently reproduce this when scrolling rapidly, or
similarly you can get a fullscreen video on e.g. YouTube and rapidly drag
around the timeline. It seems like some combo of mouse input + change in
display content.
OBSERVED RESULT
Observe flickering artifacts in the lower-right portion of the screen. The
background content flashes through the foreground intermittently.
EXPECTED RESULT
No flickering or visual artifacts. The display should render cleanly at the
configured resolution and refresh rate.
SOFTWARE/OS VERSIONS
Linux/KDE Plasma: CachyOS
KDE Plasma Version: 6.5.5
KDE Frameworks Version: 6.23.0
Qt Version: 6.10.2
ADDITIONAL INFORMATION
Whilst I'm aware this is a driver bug, as mentioned before the Hyprland devs
have implemented a fix that I think could be implemented in KDE. More details
are at:
https://wiki.hypr.land/Configuring/Variables/#opengl - look for
`nvidia_anti_flicker`
https://github.com/hyprwm/Hyprland/blob/f854b5bffbdd13cfe7edad0ee157d6947ff99619/src/render/Renderer.cpp#L2275
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