SUMMARY After updating to KDE Plasma 6.2, started experiencing tearing and lagginess issues when moving/dragging windows around. STEPS TO REPRODUCE 1. Drag a window diagonally (any angle should reproduce the problem). OBSERVED RESULT Window tears and doesn't move smoothly (with a low framerate). EXPECTED RESULT Same or similar smoothnes than when windows are dragged strictly vertically/horizontally SOFTWARE/OS VERSIONS Linux: Linux 6.11.3-zen1-1-zen KDE Plasma Version: 6.2 Qt Version: 6.7.3-2 ADDITIONAL INFORMATION using wayland using optimus manager to only use dedicated gpu (nvidia) nvidia-drm module loaded and parameters active nvidia module loaded and EnableGpuFirmware=0 Reproduced with a laptop + 2 external monitors setup. Never reproduced in laptop screen. For the external monitors, sometimes happens on both, sometimes happens in only one.
Confirmed, the same thing happens to me with an nvidia graphics card as well. The problem disappears if I have any window maximized on a virtual desktop, if I move another window over the maximized one everything works smoothly.
*** This bug has been marked as a duplicate of bug 494547 ***
(In reply to Zamundaaa from comment #2) > > *** This bug has been marked as a duplicate of bug 494547 *** Mine is not an issue of artifacts or flickering, and changing that environment variable does not resolve the issue either. The problem is specifically slowness when moving windows diagonally or shaking the mouse when it becomes big (also diagonally). Current version is 6.2.0-2 so I am not sure if it is actually related to 494547 and the problem is that arch does not have that update yet, but nothing changed from 6.2.0-1
okay, it might still come down to a similar driver issue though - synchronization being broken with multi gpu copies.
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/6690
Git commit 06a08004dc454b2a83e395922a55721416f10563 by Xaver Hugl. Committed on 23/10/2024 at 14:39. Pushed by zamundaaa into branch 'Plasma/6.2'. backends/drm: add an environment variable to force glFinish on multi gpu copies Mostly useful for debugging multi gpu glitches M +4 -2 src/backends/drm/drm_egl_layer_surface.cpp https://invent.kde.org/plasma/kwin/-/commit/06a08004dc454b2a83e395922a55721416f10563
If you can compile the Plasma/6.2 branch yourself, or once 6.2.3 is out with that commit, please test with the KWIN_DRM_FORCE_MGPU_GL_FINISH=1 environment variable set, and report back if the glitches are still there with that.
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(In reply to Zamundaaa from comment #7) > If you can compile the Plasma/6.2 branch yourself, or once 6.2.3 is out with > that commit, please test with the KWIN_DRM_FORCE_MGPU_GL_FINISH=1 > environment variable set, and report back if the glitches are still there > with that. Sorry I did not report back, glitches aren't there for me since 6.2, even without the KWIN_DRM_FORCE_MGPU_GL_FINISH=1 environment variable. Should I try with it or is this information enough? Sorry for the delay again and thank you very much!