SUMMARY kwin is able to fall back to a software cursor if its cursor plane operation is rejected by the KMS driver's atomic plane check. This works fine in most circumstances, however locks up the entire screen surface when the rejected swap occurs over the windows of certain applications. This is most apparent with Firefox, VLC, LibreOffice or GIMP on Apple Silicon Macs with hardware plane support implemented. This does not occur with Plasma panels or most KDE apps (tested with Konversation, System Settings, etc). STEPS TO REPRODUCE 1. Use an Apple Silicon Mac 2. Observe that when moving the cursor to the bottom or right edge of the screen, kwin correctly picks up that the KMS driver has rejected the swap and falls back to software cursors. 3. Open one of Firefox, VLC, LibreOffice or GIMP 4. Make sure one of the application's windows clips the bottom or right edge of the screen 5. Move the cursor to the edge of the screen clipped by the window OBSERVED RESULT Kwin considers the entire screen state to be rejected and locks up all planes until the cursor is moved away from the edge of the screen, at which point things work properly again. EXPECTED RESULT kwin should fall back to software cursors consistently SOFTWARE/OS VERSIONS Linux/KDE Plasma: Linux 6.8.9-asahi-5 (with hardware plane patches) KDE Plasma Version: 6.0.4 KDE Frameworks Version: 6.1.0 Qt Version: 6.7.0 ADDITIONAL INFORMATION The patched KMS driver can be found at https://github.com/chadmed/linux/tree/dcp-overlay-planes
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/5750
Git commit bbf4f46b280efb24c34df23253f20b195c1f347c by Xaver Hugl. Committed on 20/05/2024 at 11:14. Pushed by zamundaaa into branch 'master'. compositor_wayland: properly handle moving the cursor plane failing On test failure, the plane has to be disabled or future atomic tests fail M +24 -10 src/compositor_wayland.cpp https://invent.kde.org/plasma/kwin/-/commit/bbf4f46b280efb24c34df23253f20b195c1f347c
Git commit 772492471f60f06089fc0d3e70085ff3556b8edc by Vlad Zahorodnii, on behalf of Xaver Hugl. Committed on 20/05/2024 at 15:08. Pushed by vladz into branch 'Plasma/6.0'. compositor_wayland: properly handle moving the cursor plane failing On test failure, the plane has to be disabled or future atomic tests fail (cherry picked from commit bbf4f46b280efb24c34df23253f20b195c1f347c) M +24 -10 src/compositor_wayland.cpp https://invent.kde.org/plasma/kwin/-/commit/772492471f60f06089fc0d3e70085ff3556b8edc