[Intel-gfx] [PATCH 5/7] drm/i915/uc: Skip reset preparation if GuC is already dead

[Michal Wajdeczko]

On Fri, 17 May 2019 22:08:56 +0200, Chris Wilson  
<chris at chris-wilson.co.uk> wrote:

> Quoting Michal Wajdeczko (2019-05-17 19:01:06)
>> On Fri, 17 May 2019 19:14:01 +0200, Chris Wilson
>> <chris at chris-wilson.co.uk> wrote:
>>
>> > Quoting Michal Wajdeczko (2019-05-17 18:11:07)
>> >> On Fri, 17 May 2019 18:31:31 +0200, Chris Wilson
>> >> <chris at chris-wilson.co.uk> wrote:
>> >>
>> >> > Quoting Michal Wajdeczko (2019-05-17 17:22:25)
>> >> >> We may skip reset preparation steps if GuC is already sanitized.
>> >> >>
>> >> >> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
>> >> >> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>> >> >> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> >> >> ---
>> >> >>  drivers/gpu/drm/i915/intel_uc.c | 3 +++
>> >> >>  1 file changed, 3 insertions(+)
>> >> >>
>> >> >> diff --git a/drivers/gpu/drm/i915/intel_uc.c
>> >> >> b/drivers/gpu/drm/i915/intel_uc.c
>> >> >> index 86edfa5ad72e..36c53a42927c 100644
>> >> >> --- a/drivers/gpu/drm/i915/intel_uc.c
>> >> >> +++ b/drivers/gpu/drm/i915/intel_uc.c
>> >> >> @@ -499,6 +499,9 @@ void intel_uc_reset_prepare(struct
>> >> drm_i915_private
>> >> >> *i915)
>> >> >>         if (!USES_GUC(i915))
>> >> >>                 return;
>> >> >>
>> >> >> +       if (!intel_guc_is_alive(guc))
>> >> >> +               return;
>> >> >
>> >> > Does it not replace "if (!USES_GUC(i915))"?
>> >>
>> >> Yes it can, as we will never fetch/upload fw if we don't plan to use  
>> it
>> >> ;)
>> >>
>> >> Btw, I'm thinking of renaming intel_guc_is_alive to  
>> intel_guc_is_loaded
>> >> or intel_guc_is_started to better describe what this function is
>> >> reporting,
>> >> as one can think that intel_guc_is_alive is actually checking that  
>> GuC
>> >> fw
>> >> is responsive, which in general might not be the same as "loaded"
>> >
>> > Either seems reasonable, though there might be good reason to have  
>> both
>> > :)
>> >
>> > intel_guc_is_loaded
>> > intel_guc_has_started / intel_guc_is_active
>>
>> On GuC load failure, or on reset, we immediately sanitize fw load  
>> status,
>> so until we provide real runtime connectivity check, if ever be  
>> required,
>> I assume we can stay with just one function: intel_guc_is_loaded, ok?
>
> Would a similar one for huc also work? Would it be reliable enough to
> replace HUC_STATUS query? (Seems silly to wake the device up just to
> answer if we've loaded the firmware successfully.)

I'm not sure that we can drop HUC_STATUS query as maybe this bit can
go off (who can confirm that?) but we definitely can replace HAS_HUC
(btw it should be USES_HUC) with new intel_huc_is_loaded

Michal