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

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> 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

Bugzilla fairy might surprise us after a good weekend rest.

-Mika

> -Chris
>
> -- 
> Chris Wilson, Intel Open Source Technology Centre