[Intel-gfx] Regression in i915

[Chris Wilson]

Quoting Larry Finger (2020-04-07 18:27:52)
> Chris,
> 
> With a recent pull of kernel head, my Toshiba laptop with an i915 graphics card 
> fails to boot. It hangs at the point where it should switch to a graphics 
> screen. I bisected the problem to
> 
> commit 7dc8f1143778a35b190f9413f228b3cf28f67f8d
> Author: Chris Wilson <chris at chris-wilson.co.uk>
> Date:   Wed Mar 11 16:03:10 2020 +0000
> 
>      drm/i915/gem: Drop relocation slowpath
> 
> The lspci command reports my card as
> 00:02.0 VGA compatible controller [0300]: Intel Corporation 4th Gen Core 
> Processor Integrated Graphics Controller [8086:0416] (rev 06)
> 
> Has this problem been reported, and is there a fix?

2 possible causes for 2 very different symptoms are in flight.
But neither would strictly be a hang; the most blatant one would be the
display server triggering an EFAULT. The patches are currently sitting
in the drm-intel-next-fixes queue; a quick test of drm-tip would confirm
how worried one needs to be.
-Chris