[Intel-gfx] [PATCH] drm/i915: Broaden application of set-domain(GTT)

[Chris Wilson]

On Tue, Oct 14, 2014 at 01:47:36PM +0100, Chris Wilson wrote:
> Previously, this was restricted to only operate on bound objects - to
> make pointer access through the GTT to the object coherent with writes
> to and from the GPU. A second usecase is drm_intel_bo_wait_rendering()
> which at present does not function unless the object also happens to
> be bound into the GGTT (on current systems that is becoming increasingly
> rare, especially for the typical requests from mesa). A third usecase is
> a future patch wishing to extend the coverage of the GTT domain to
> include objects not bound into the GGTT but still in its coherent cache
> domain. For the latter pair of requests, we need to operate on the
> object regardless of its bind state.
> 
> v2: After discussion with Akash, we came to the conclusion that the
> get-pages was required in order for accurate domain tracking in the
> corner cases (like the shrinker) and also useful for ensuring memory
> coherency with earlier cached CPU mmaps in case userspace uses exotic
> cache bypass (non-temporal) instructions.
> 
> Cc: Akash Goel <akash.goel at intel.com>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Akash, are you happy with this? Could you bless this with an r-b?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre