How to get useful information other than "the whole system locks up"?

[Braiam]

Hi,

I have a Sapphire Technology Hawaii XT (R9 290X) using amdgpu driver
with kernel 5.1.0-rc3.
The issue happens with current 4.19.0 debian testing, 4.20-trunk,
5.0.0-trunk and rc2 and 3.

It usually happens when I'm reproducing video, but I haven't figured
out a way to reproduce it. It
happened once without reproducing. I'm aware that the support is
experimental, but radeon
driver doesn't seems capable of direct rendering on this card dropping
to llvmepipe.

I had a ssh server installed in case I could log in while it crashes,
and the only relevant
line I found was:

drm:amdgpu job timeout [amdgpu]] **ERROR** ring gfx timeout, signaled
seq=399919, emitted seq=399921

But that turned several bug reports which seems to have been fixed and
the context and symptoms are too different to mine.

I have tried forcing the amdgpu xorg driver with same results (was
using radeon).

-- 
Braiam