[Intel-gfx] [PATCH] drm/i914/guc: Fix resume on platforms w/o GuC submission but enabled

[Hiatt, Don]

> > From: Ceraolo Spurio, Daniele <daniele.ceraolospurio at intel.com>
> > Sent: Monday, October 28, 2019 11:30 AM
> > To: Hiatt, Don <don.hiatt at intel.com>; intel-gfx at lists.freedesktop.org
> > Subject: Re: [Intel-gfx] [PATCH] drm/i914/guc: Fix resume on platforms w/o
> GuC
> > submission but enabled
> >
> >
> >
> > On 10/28/19 11:17 AM, Hiatt, Don wrote:
> > >> From: Ceraolo Spurio, Daniele <daniele.ceraolospurio at intel.com>
> > >> Sent: Monday, October 28, 2019 9:44 AM
> > >> To: Hiatt, Don <don.hiatt at intel.com>; intel-gfx at lists.freedesktop.org
> > >> Subject: Re: [Intel-gfx] [PATCH] drm/i914/guc: Fix resume on platforms w/o
> > GuC
> > >> submission but enabled
> > >>
> > >>
> > >>
> > >> On 10/24/19 9:29 AM, don.hiatt at intel.com wrote:
> > >>> From: Don Hiatt <don.hiatt at intel.com>
> > >>>
> > >>> Check to see if GuC submission is enabled before requesting the
> > >>> EXIT_S_STATE action.
> > >>>
> > >>
> > >> You're only skipping the resume, but does it make any sense to do the
> > >> suspend action if we're not going to call the resume one? Does guc do
> > >> anything in the suspend action that we still require? I thought it only
> > >> saved the submission status, which we don't care about if guc submission
> > >> is disabled.
> > >>
> > >> Daniele
> > >>
> > >
> > > Hi Daniele,
> > >
> > > I tried skipping the suspend all together but then the HuC gets timeouts
> > > waiting for the GuC to acknowledge the authentication request which leads
> to
> > a
> > > wedged GPU. ☹
> > >
> >
> > Do we know why? if we skip the suspend/resume H2G and reload the blobs
> > after resetting the HW it should look like a clean boot from the HW
> > perspective, so the fact that HuC auth times out feels weird and might
> > hide other issues. I asked one of the guc devs and he also thinks this
> > is not expected behavior. Can you dig a bit more?
> >
> > Thanks,
> > Daniele
> >
> 
> No idea why but I'll do some digging and see what I find.
> 
> Thanks!
> 
> don
> 
Hi Daniele,

I was a little overzealous on my removal of suspend/resume. We still need to go
through the steps of enable/disable GuC communication on suspend/resume but
just not send the GuC action. My first attempt was not handling the GuC communication
properly so that is why I was seeing the HuC authentication timesouts.

I'm submitting new patch -- with the proper 'drm/i915' -- and will CC you.

Thanks!

don


> > > BTW, I made a typo in the patch, should be 'drm/i915' not '914', I'll fix that
> > > up.
> > >
> > > Thanks,
> > >
> > > don
> > >
> > >
> > >>> On some platforms (e.g. KBL) that do not support GuC submission, but
> > >>> the user enabled the GuC communication (e.g for HuC authentication)
> > >>> calling the GuC EXIT_S_STATE action results in lose of ability to
> > >>> enter RC6. Guard against this by only requesting the GuC action on
> > >>> platforms that support GuC submission.
> > >>>
> > >>> I've verfied that intel_guc_resume() only gets called when driver
> > >>> is loaded with: guc_enable={1,2,3}, all other cases (no args,
> > >>> guc_enable={0,-1} the intel_guc_resume() is not called.
> > >>>
> > >>> Signed-off-by: Don Hiatt <don.hiatt at intel.com>
> > >>> ---
> > >>>    drivers/gpu/drm/i915/gt/uc/intel_guc.c | 5 ++++-
> > >>>    1 file changed, 4 insertions(+), 1 deletion(-)
> > >>>
> > >>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.c
> > >> b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
> > >>> index 37f7bcbf7dac..33318ed135c0 100644
> > >>> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.c
> > >>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
> > >>> @@ -565,7 +565,10 @@ int intel_guc_resume(struct intel_guc *guc)
> > >>>    		GUC_POWER_D0,
> > >>>    	};
> > >>>
> > >>> -	return intel_guc_send(guc, action, ARRAY_SIZE(action));
> > >>> +	if (guc->submission_supported)
> > >>> +		return intel_guc_send(guc, action, ARRAY_SIZE(action));
> > >>> +
> > >>> +	return 0;
> > >>>    }
> > >>>
> > >>>    /**
> > >>>
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