[Intel-gfx] [PATCH] drm/i915: Enable full PPGTT on gen7

[Chris Wilson]

On Fri, Sep 05, 2014 at 02:13:16PM +0100, Michel Thierry wrote:
> Use full PPGTT as the default option in gen7.
> Note that aliasing PPGTT is the default option for gen8 (see HAS_PPGTT).
> 
> This may well come back to bite me later.

Indeed. So something I spotted was that bspec mentions that the per-ring
PDE registers (RING_PP_DIR_DCLV and RING_PP_DIR_BASE) are stored in the
logical context and so the registers are restored along with the
context. If this is correct what happens when we switch logical contexts
on RCS whilst we have active work on BCS etc? Does this mean that we
have to serialise context switches across rings, or is my reading of the
bspec false?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre