[Intel-gfx] [PATCH 08/17] drm/i915: Don't look at pg_dirty_rings for aliasing ppgtt

[Chris Wilson]

On Thu, Apr 23, 2015 at 08:56:40PM +0200, Daniel Vetter wrote:
> Yeah, but I didn't really see the point in the debug infrastructure for
> aliasing ppgtt. The pde loading is done somewhere completely else than for
> full ppgtt. And if we forget to load the pdes the effects are obvious,
> whereas failing to reload when changes happen with full ppgtt is much
> harder to spot quickly. So I opted to undo those checks again, they have
> been defunct before my changes anyway.

But they did just serve a purpose. They said we were not skipping the
no-op context switches.

I disagree though and that we want to reduce the differences in handling
the two different types of mm. There is no good reason to bake in
knowledge of full-ppgtt vs aliasing-ppgtt here as the decision whether
to do the mm switch is purely decided on the validity of the
current/next PD.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre