[Intel-gfx] [PATCH] drm/i915: Don't clflush purged objects on unbind

[Chris Wilson]

On Wed, 09 Dec 2009 09:27:15 -0800, Eric Anholt <eric at anholt.net> wrote:
> Yeah, the question was whether there was any danger in handing pages
> back to the system where there may be read cachelines that are actually
> not valid.  We couldn't convince ourselves last night that that was
> definitely safe.  (Would the CPU drop a write of zeroes to a cacheline
> where the cache said it was already full of zeroes?)

Ooh, nasty. Do all DMA engines have similar issues with needing to flush
the CPU cache-lines?
-ickle

-- 
Chris Wilson, Intel Open Source Technology Centre