Mesa OpenGL Threading Messed Up Cursor Handling With KDE Wayland - Fixed Now

If you habitually ride Mesa Git for the latest and greatest open-source AMD Radeon graphics driver code and use the KDE Plasma desktop with Wayland, you may have noticed a glitchy cursor recently. Fortunately, that's now fixed up with today's Mesa Git code and ended up stemming from the recent global enabling of Mesa OpenGL threading.

Last month RadeonSI Gallium3D enabled OpenGL threading by default in an effort to improve the Linux gaming experience. VOer the past few years this Mesa "glthread" code has been selectively enabled on a per-game basis but now for Mesa 22.3 is deemed stable enough and offering enough widespread performance benefits to just enable by default. Besides the per-game whitelisting, the other alternative for users on existing Mesa versions has been to toggle the feature with the mesa_glthread=true environment variable.

Recently it's been reported that for those AMD Radeon users running Mesa Git in recent weeks has caused cursor issues under KDE Plasma running Wayland with KWin. There have been cursor detection issues and unexpected behavior around cursor movement when running KDE Plasma on Wayland with the recent Mesa 22.3-devel state. This is not another KDE/KWin bug per se but turned out to be a problem with Mesa OpenGL threading being flipped on.

Well, the fix that has been merged is to just blacklist "kwin_wayland" from having OpenGL threading enabled. The workaround was merged today to just disable mesa_glthread behavior for the kwin_wayland process. This will keep OpenGL threading for RadeonSI enabled by default for all other processes on the system to enjoy the performance benefits primarily for Linux gaming with this open-source Radeon OpenGL driver.