Re: [PATCH] drm/i915: Track frontbuffer invalidation/flushing

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Jun 19, 2014 at 02:02:26PM +0100, Chris Wilson wrote:
> On Thu, Jun 19, 2014 at 02:41:27PM +0200, Daniel Vetter wrote:
> > @@ -3626,6 +3628,8 @@ i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
> >  		obj->dirty = 1;
> >  	}
> >  
> > +	intel_fb_obj_invalidate(obj, NULL);
> We should only invalidate when we start writing.
> 
> > +
> >  	trace_i915_gem_object_change_domain(obj,
> >  					    old_read_domains,
> >  					    old_write_domain);
> > @@ -3962,6 +3966,8 @@ i915_gem_object_set_to_cpu_domain(struct drm_i915_gem_object *obj, bool write)
> >  		obj->base.write_domain = I915_GEM_DOMAIN_CPU;
> >  	}
> >  
> > +	intel_fb_obj_invalidate(obj, NULL);
> Again only for writes. Now I think that this is skippable as the CPU
> domain is explicitly incoherent with display, but for symmetry of
> invalidate/flush it is required.

Good call, will fix up both places.
> 
> > +
> >  	trace_i915_gem_object_change_domain(obj,
> >  					    old_read_domains,
> >  					    old_write_domain);
> 
> > +void intel_frontbuffer_flush(struct drm_device *dev,
> > +			     unsigned frontbuffer_bits)
> > +{
> > +	struct drm_i915_private *dev_priv = dev->dev_private;
> > +
> > +	/* Delay flushing when rings are still busy.*/
> > +	mutex_lock(&dev_priv->fb_tracking.lock);
> > +	frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
> > +	mutex_unlock(&dev_priv->fb_tracking.lock);
> > +
> > +	intel_mark_fb_busy(dev, frontbuffer_bits, NULL);
> > +
> > +	intel_edp_psr_exit(dev);
> Please tell me to plan to change this functions name. As we certainly
> don't want to disable PSR here, but hopefully reenable it.

Yeah, the psr patch on top of this splits psr_exit into psr_invalidate and
psr_flush and generally dtrt.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch