[Intel-gfx] [PATCH 09/15] drm/i915/guc: Move check for fast memcpy_wc to relay creation

[Michał Winiarski]

On Tue, Feb 27, 2018 at 03:37:25PM +0100, Michal Wajdeczko wrote:
> On Tue, 27 Feb 2018 13:52:24 +0100, Michał Winiarski
> <michal.winiarski at intel.com> wrote:
> 
> > We only need those fast memcpy_wc when we're using relay to read
> > continuous GuC log. Let's prevent the user from creating a relay if we
> > know we won't be able to keep up with GuC.
> > 
> > Signed-off-by: Michał Winiarski <michal.winiarski at intel.com>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> > Cc: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> > Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_guc_log.c | 20 ++++++++++----------
> >  1 file changed, 10 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_guc_log.c
> > b/drivers/gpu/drm/i915/intel_guc_log.c
> > index 4dee65692f5f..d2aca10ab986 100644
> > --- a/drivers/gpu/drm/i915/intel_guc_log.c
> > +++ b/drivers/gpu/drm/i915/intel_guc_log.c
> > @@ -452,16 +452,6 @@ int intel_guc_log_create(struct intel_guc *guc)
> > 	GEM_BUG_ON(guc->log.vma);
> > -	/*
> > -	 * We require SSE 4.1 for fast reads from the GuC log buffer and
> > -	 * it should be present on the chipsets supporting GuC based
> > -	 * submisssions.
> > -	 */
> > -	if (WARN_ON(!i915_has_memcpy_from_wc())) {
> > -		ret = -EINVAL;
> > -		goto err;
> > -	}
> > -
> >  	vma = intel_guc_allocate_vma(guc, GUC_LOG_SIZE);
> >  	if (IS_ERR(vma)) {
> >  		ret = PTR_ERR(vma);
> > @@ -568,6 +558,16 @@ int intel_guc_log_relay_open(struct intel_guc *guc)
> >  		goto out_unlock;
> >  	}
> > +	/*
> > +	 * We require SSE 4.1 for fast reads from the GuC log buffer and
> > +	 * it should be present on the chipsets supporting GuC based
> > +	 * submisssions.
> > +	 */
> > +	if (!i915_has_memcpy_from_wc()) {
> > +		ret = -EINVAL;
> 
> hmm, maybe -ENODEV as this is not user fault

ENODEV means that we're not using GuC.
-ENXIO?

-Michał

> 
> > +		goto out_unlock;
> > +	}
> > +
> >  	ret = guc_log_relay_create(guc);
> >  	if (ret)
> >  		goto out_unlock;