SUMMARY When GPU usage is high (mostly in games) the mouse cursor stutters when it's hardware accelerated. Making the mouse software accelerated with `KWIN_FORCE_SW_CURSOR=1` fixes the issue (but created artifacts). STEPS TO REPRODUCE 1. Run a game 2. Uncap FPS to have GPU usage around 99% 3. Mouse stuttering (outside of game even) 4. Enable SW acceleration 5. No stutter on 99% GPU usage OBSERVED RESULT System stuttering EXPECTED RESULT No stutters (maybe some but not like this) SOFTWARE/OS VERSIONS Linux: ostree-image-signed:docker://ghcr.io/ublue-os/kinoite-main:latest (available in About System) KDE Plasma Version: 5.27.10 KDE Frameworks Version: 5.115.0 Qt Version: 5.15.12 ADDITIONAL INFORMATION There's a reddit post with this issue as well: https://www.reddit.com/r/linux_gaming/comments/19694tk/everything_gets_laggy_when_gpu_gets_close_to_100/
In 5.27 hardware cursor updates were still tied to the rest of the screen; it stuttering with very high GPU load wouldn't be entirely unexpected - and that's fixed in 6.0. If it doesn't happen with the software cursor though, then that's a driver bug. Please report this to your GPU vendor (if it's AMD like in the Reddit post, you can do that at https://gitlab.freedesktop.org/drm/amd/-/issues)