[Intel-gfx] "BUG: unable to handle kernel NULL pointer dereference at 0000000000000070" in [i915] reset_common_ring

[Chris Wilson]

Quoting Bjørn Mork (2017-10-19 11:24:57)
> Hello,
> 
> I get these Oopses from time to time, but unfortunately(?) not often
> enough to be anywhere near reproducible.  But they seem to be related to
> whatever activites my laptop/X-server/driver/gpu/screen is doing while
> I'm not present. The oops happens when I'm away for a while.  So I guess
> it might be something related to screensaver and/or power saving
> actions.
> 
> There is always a GPU HANG prior to the Oops, so these events are
> probably related.  

It is, but the oops implies that hw got lost along the way. You need a
more recent kernel to avoid that trap, and at a guess
intel_iommu=igfx_off to avoid the hangs in the first place.
-Chris