[Intel-gfx] [PATCH] drm/i915: check ACTHD of all rings

[Chris Wilson]

On Sun, 27 Nov 2011 18:58:17 +0100, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> Otherwise hangcheck spuriously fires when running blitter/bsd-only
> workloads.
> 
> Contrary to a similar patch by Ben Widawsky this does not check
> INSTDONE of the other rings. Chris Wilson implied that in a failure to
> detect a hang, most likely because INSTDONE was fluctuating. Thus only
> check ACTHD, which as far as I know is rather reliable. Also, blitter
> and bsd rings can't launch complex tasks from a single instruction
> (like 3D_PRIM on the render with complex or even infinite shaders).
> 
> This fixes spurious gpu hang detection when running
> tests/gem_hangcheck_forcewake on snb/ivb.
> 
> Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre