SUMMARY When using KWin Wayland, the XWayland server started by it will have the wrong refresh rate set. In my case it is 144Hz for a 240Hz monitor. For wayland itself, the refresh rate is correct. This bug can be seen when running XWayland apps as well, for example: Chromium and mpv (with xwayland) will report the display refresh rate as 143Hz. This can (and does) result in laggy, juddery experience. STEPS TO REPRODUCE 1. Start KWin Wayland 2. run xrandr or check X apps OBSERVED RESULT XWayland is set to the wrong refresh rate (144Hz in my case) EXPECTED RESULT XWayland refresh rate should be in sync with the Wayland one (240Hz) SOFTWARE/OS VERSIONS Linux/KDE Plasma: Arch Linux 5.23.1 KDE Plasma Version: 5.23.1 KDE Frameworks Version: 5.87.0 Qt Version: 5.15.2 GPU: NVIDIA Turing ADDITIONAL INFORMATION
Created attachment 142901 [details] output from kscreen-doctor-o
Created attachment 142902 [details] output from qdbus
Created attachment 142903 [details] output from xrandr
The refresh rate of nested kwin_wayland is hardcoded to 60Hz. Did you mean host kwin_wayland or nested kwin_wayland?
host kwin_wayland => kwin_wayland running on top of DRM nested kwin_wayland => windowed kwin_wayland
(In reply to Vlad Zahorodnii from comment #4) > The refresh rate of nested kwin_wayland is hardcoded to 60Hz. Did you mean > host kwin_wayland or nested kwin_wayland? I mean kwin_wayland started with "kwin_wayland ... --xwayland ..". This is usually referred to as a "nested session" in KDE documentation I've read, am I using the wrong terminology?
(In reply to Vlad Zahorodnii from comment #5) > host kwin_wayland => kwin_wayland running on top of DRM > nested kwin_wayland => windowed kwin_wayland Host.
*** This bug has been marked as a duplicate of bug 444303 ***