https://bugs.freedesktop.org/show_bug.cgi?id=109692
--- Comment #13 from Andrey Grodzovsky andrey.grodzovsky@amd.com --- Also, in the meanwhile try reverting this 2 patches and see if it helps -
3741540 Andrey Grodzovsky 5 weeks ago drm/sched: Rework HW fence processing. 222b5f0 Andrey Grodzovsky 5 weeks ago drm/sched: Refactor ring mirror list handling.
They are causing this deadlock.