[Intel-gfx] [PATCH 04/11] drm/i915/tgl: Add extra hdc flush workaround

[Chris Wilson]

Quoting Mika Kuoppala (2019-10-15 16:44:42)
> In order to ensure constant caches are invalidated
> properly with a0, we need extra hdc flush after invalidation.
> 
> v2: use IS_TGL_REVID (Chris)
> 
> References: HSDES#1604544889
> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris