From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [PATCH 17/30] drm/i915: Do not clflush snooped
	objects
Date: Wed, 13 Apr 2011 18:34:57 +0100
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To: Daniel Vetter <daniel@ffwll.ch>
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On Wed, 13 Apr 2011 18:04:38 +0200, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Tue, Apr 12, 2011 at 09:31:45PM +0100, Chris Wilson wrote:
> > +	/* If the GPU is snooping the contents of the CPU cache,
> > +	 * we do not need to clear the CPU cache lines. Instead we need
> > +	 * to be sure to flush/invalidate the RENDER cache when the contents
> > +	 * must be refreshed.
> > +	 */
> 
> The "Instead we need to be sure to flush the RENDER cache ..." is a bit
> confusing to me: There's no instead, we have to do this always when
> writing with the cpu. Besides this minor comment-nitpick it makes sense.

I changed the comment to:

/* If the GPU is snooping the contents of the CPU cache,
 * we do not need to manually clear the CPU cache lines.  Instead,
 * the caches are only snooped when the render cache is
 * flushed/invalidated.  As we always have to emit invalidations
 * and flushes when moving into and out of the RENDER domain, correct
 * snooping behaviour occurs naturally as the result of our domain
 * tracking.
 */
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre