[Intel-gfx] [PATCH] drm/i915: Allow unready gpu to be reset on gen8

[Chris Wilson]

On Fri, Oct 30, 2015 at 05:18:18PM +0200, Mika Kuoppala wrote:
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > On Fri, Oct 30, 2015 at 04:43:49PM +0200, Mika Kuoppala wrote:
> >> Gen9 has had demonstrated cases where forcing a not ready gpu
> >> into reset has caused system hang [1].
> >> 
> >> Gen8 has never to this date demonstrated such behaviour.
> >> 
> >> In our CI tests bsw sometimes ends up in a state where it claims it
> >> is not ready for reset, based on reset request, after gpu hang.
> >> 
> >> Allow gen8 to reset even after claims of nonreadiness in order
> >> to keep the gpu accessible. Enhance logging so that it will be
> >> clear what conditions led to decision of proceeding or bailing out,
> >> so that we will spot if this way of forcing our will against gpu turns
> >> out to be foolhardy.
> >> 
> >> References [1]: https://bugs.freedesktop.org/show_bug.cgi?id=89959
> >> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> >> Cc: Tomi Sarvela <tomix.p.sarvela at intel.com>
> >> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/intel_uncore.c | 9 ++++++++-
> >>  1 file changed, 8 insertions(+), 1 deletion(-)
> >> 
> >> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> >> index f0f97b2..47c17f2 100644
> >> --- a/drivers/gpu/drm/i915/intel_uncore.c
> >> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> >> @@ -1504,7 +1504,14 @@ not_ready:
> >>  		I915_WRITE(RING_RESET_CTL(engine->mmio_base),
> >>  			   _MASKED_BIT_DISABLE(RESET_CTL_REQUEST_RESET));
> >>  
> >> -	return -EIO;
> >
> > Where's the reference for where we hit this EIO on gen8?
> >
> 
> Internal CI logs, relevant part cutpasted below. If you want
> full log holler me in irc.

So you are saying that's there no bugzilla for this... :-p
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre