From: Ville Syrjälä <ville.syrj...@linux.intel.com>

BSpec recommends using 8x4 hashing mode when MSAA is used. But in
practice 16x4 seems to have a slight edge in performance (on IVB and
HSW at least). So just use 16x4.

Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index c51b64a..ba5fee4 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4856,6 +4856,13 @@ static void haswell_init_clock_gating(struct drm_device 
*dev)
        I915_WRITE(CACHE_MODE_1,
                   _MASKED_BIT_ENABLE(PIXEL_SUBSPAN_COLLECT_OPT_DISABLE));
 
+       /*
+        * BSpec recommends 8x4 when MSAA is used,
+        * however in practice 16x4 seems fastest.
+        */
+       I915_WRITE(GEN7_GT_MODE,
+                  GEN6_WIZ_HASHING_MASK | GEN6_WIZ_HASHING_16x4);
+
        /* WaSwitchSolVfFArbitrationPriority:hsw */
        I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) | HSW_ECOCHK_ARB_PRIO_SOL);
 
-- 
1.8.3.2

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