[Intel-gfx] [PATCH v2] drm/i915: Apply the GTT write flush for all !llc machines

[Chris Wilson]

Quoting Ville Syrjälä (2017-09-07 19:50:13)
> On Thu, Sep 07, 2017 at 07:45:20PM +0100, Chris Wilson wrote:
> > We also see the delayed GTT write issue on i915g/i915gm, so let's
> > presume that it is a universal problem for all !llc machines, and that we
> > just haven't yet noticed on g33, gen4 and gen5 machines.
> > 
> > v2: Use a register that exists on all platforms
> > 
> > Testcase: igt/gem_mmap_gtt/coherency # i915gm
> > References: https://bugs.freedesktop.org/show_bug.cgi?id=102577
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Seems to be doing the trick nicely. i915gm has settled down now for a
long run to hunt for coherency issues, and bsw/bxt are still happy.

Pushed, thanks for the review, especially catching ACTHD migrated.
-Chris