Update after switching HWE kernels and dropping the local workaround. **Kernel change** - 2026-07-17: cold-booted into Ubuntu HWE **7.0.0-28-generic** (`linux-generic-hwe-24.04`, in-distro; GRUB default). Same machine (Dell Precision 5690 / Meteor Lake iGPU, X11 / Plasma 5.27). - Mesa still **25.2.8-0ubuntu0.24.04.2** (unchanged).
**Workaround status** - Removed `LIBGL_DRI3_DISABLE=1` for `kwin_x11` and `plasmashell` on that boot (raw DRI3/GLX again). Compositing remained hardware OpenGL on Intel Arc MTL. **Re-test on raw DRI3 / 7.0** 1. Same notification-storm reproducer that previously wedged plasmashell on 6.17 (bursts of short-lived notify-send popups for ~40 minutes): **completed with no hang**. Same `kwin_x11` / `plasmashell` PIDs stayed healthy for the whole run; D-Bus responsive throughout. 2. Continued normal desktop use on the same boot, including idle auto-lock cycles, for **~3 days** (boot 2026-07-17 13:02 → check 2026-07-20). Forensic probe armed the whole time: **zero** further kwin/plasmashell swap hangs captured. **Interpretation** This still fits a Mesa DRI3/Present race that 6.17 i915 present/vblank timing made easy to hit, and that **7.0 does not expose the same way** under our stress. The Mesa 26.1.5 `send_sbc` fix remains a good candidate for noble 25.2.x (we are still on 25.2.8), but day-to-day we no longer need `LIBGL_DRI3_DISABLE` on 7.0. Happy to re-run the storm or capture more traces if a triager wants data on 7.0 vs 6.17. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2161079 Title: kwin_x11 and plasmashell hang forever in DRI3 glXSwapBuffers after HWE kernel 6.17 update (Meteor Lake, X11) — fix candidate in Mesa 26.1.5 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/2161079/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
