[Intel-gfx] [RFC 2/2] drm/i915: Use i915_vma_iomap from the ringbuffer

[Chris Wilson]

On Tue, Apr 12, 2016 at 04:56:52PM +0100, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Similarly to i915_gem_object_pin_map on LLC platforms, we can
> use the new VMA based io mapping on !LLC to decrease the cost
> of ringbuf pinning and unpinning.

If you are going to mention pin_map, you open up the discussion that we
can avoid the mappable apertures requirement on !llc if we use pin_map
with a pgprot_writecombine. That's my preferred solution, caching the
ioremap is just a stopgap, or fallback for when we can't use direct CPU
access.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre