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

[Chris Wilson]

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.)
-Chris