The desktop freezes related to sdma0 timeout errors are definitely not fixed
with the addition of this third patch. I just had another one while working in
WebStorm and PyCharm for a couple of hours.

Kernel in use was/is `drm.fixes.5.4.2019.10.09.r0.g083164dbdb17-3` with
- drm-amdgpu-do-not-execute-0-sized-IBs.patch
- drm-amdgpu-sdma5-fix-mask-value-of-POLL_REGMEM-packet-for-pipe-sync.patch
- sdma-read-delay.patch

[103602.655947] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring sdma0 timeout,
signaled seq=11405753, emitted seq=11405755
[103602.656061] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* Process information:
process Xorg pid 710 thread Xorg:cs0 pid 711
[103602.656062] [drm] GPU recovery disabled.

Unfortunately, I forgot to run `sudo umr -R sdma0` after ssh-ing into my system
and reading the dmesg output, so no further debug output from me. :(