It looks like the Nvidia kernel driver just stopped accepting new frames from the Wayland session:
Sep 06 18:52:38 Nexus kernel: [drm:nv_drm_atomic_commit [nvidia_drm]] *ERROR* [nvidia-drm] [GPU ID 0x00000a00] Flip event timeout on head 0 Sep 06 18:52:41 Nexus kernel: [drm:nv_drm_atomic_commit [nvidia_drm]] *ERROR* [nvidia-drm] [GPU ID 0x00000a00] Flip event timeout on head 1 (also mentioned in bug 2069694) Do you find the problem usually coincides with those log messages? Please try disabling the "atomic" feature by adding this to /etc/environment: MUTTER_DEBUG_FORCE_KMS_MODE=simple and reboot. ** Tags added: nvidia ** Tags added: nvidia-wayland wayland wayland-session ** Changed in: mutter (Ubuntu) Status: New => Incomplete ** Package changed: mutter (Ubuntu) => nvidia-graphics-drivers-550 (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2079867 Title: [nvidia] Screen freeze on Wayland using Nvidia 550 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-550/+bug/2079867/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs