drm/i915: Clarify WaDisable4x2SubspanOptimization situation for VLV

WaDisable4x2SubspanOptimization isn't listed for VLV in the workaround
database, but BSpec says that the relevant bit must be set. Add a
comment to remind people of this.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2014-01-22 21:33:03 +02:00 committed by Daniel Vetter
parent 46680e0a43
commit afd58e79ff
1 changed files with 4 additions and 0 deletions

View File

@ -4945,6 +4945,10 @@ static void valleyview_init_clock_gating(struct drm_device *dev)
I915_WRITE(MI_ARB_VLV, MI_ARB_DISPLAY_TRICKLE_FEED_DISABLE);
/*
* BSpec says this must be set, even though
* WaDisable4x2SubspanOptimization isn't listed for VLV.
*/
I915_WRITE(CACHE_MODE_1,
_MASKED_BIT_ENABLE(PIXEL_SUBSPAN_COLLECT_OPT_DISABLE));