Re: [Intel-gfx] [PATCH v2] drm/i915/guc: Fix revocation of non-persistent contexts

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 04/10/2022 16:13, Ceraolo Spurio, Daniele wrote:
> On 10/4/2022 4:14 AM, Tvrtko Ursulin wrote:
>>
>> On 03/10/2022 13:16, Tvrtko Ursulin wrote:
>>> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>>>
>>> Patch which added graceful exit for non-persistent contexts missed the
>>> fact it is not enough to set the exiting flag on a context and let the
>>> backend handle it from there.
>>>
>>> GuC backend cannot handle it because it runs independently in the
>>> firmware and driver might not see the requests ever again. Patch also
>>> missed the fact some usages of intel_context_is_banned in the GuC 
>>> backend
>>> needed replacing with newly introduced intel_context_is_schedulable.
>>>
>>> Fix the first issue by calling into backend revoke when we know this is
>>> the last chance to do it. Fix the second issue by replacing
>>> intel_context_is_banned with intel_context_is_schedulable, which should
>>> always be safe since latter is a superset of the former.
>>>
>>> v2:
>>>   * Just call ce->ops->revoke unconditionally. (Andrzej)
>>
>> CI is happy - could I get some acks for the GuC backend changes please?
> 
> I think we still need to have a longer conversation on the revoking 
> times, but in the meantime this fixes the immediate concerns, so:
> 
> Acked-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Thanks, I've pushed it so should unbreak 6.0 via stable.

For follow up work I am okay either with a fixes 20ms timeout (this was 
enough for users which originally reported it), or go with fully 
configurable? Latter feels a bit over the top since it would then me a 
kconfig and sysfs to align with the normal preempt timeout.

Regards,

Tvrtko