I tried to enable NIR using R600_DEBUG=nir, I got a different behaviour on GFX
timeout. 
[Feb 1 19:44] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240122] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[Feb 1 19:45] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240145] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240170] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.239953] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240061] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240340] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[Feb 1 19:46] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240003] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240173] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240074] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.239890] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[Feb 1 19:44] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240122] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[Feb 1 19:45] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240145] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240170] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.239953] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240061] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240340] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[Feb 1 19:46] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240003] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240173] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered
[ +10.240074] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, but
soft recovered

I get a a looping error message like the above but I can kill the application
from ssh. Display is once again usable, no hard reset is required.