drm/i915: Implement WaVSRefCountFullforceMissDisable

Implements WaVSRefCountFullforceMissDisable as documented in the BSpec
3D workarounds chapter.

Cc: Paulo Zanoni <przanoni@gmail.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -741,6 +741,7 @@
 #define   GEN7_FF_TS_SCHED_HS0		(0x3<<16)
 #define   GEN7_FF_TS_SCHED_LOAD_BALANCE	(0x1<<16)
 #define   GEN7_FF_TS_SCHED_HW		(0x0<<16) /* Default */
+#define   GEN7_FF_VS_REF_CNT_FFME	(1 << 15)
 #define   GEN7_FF_VS_SCHED_HS1		(0x5<<12)
 #define   GEN7_FF_VS_SCHED_HS0		(0x3<<12)
 #define   GEN7_FF_VS_SCHED_LOAD_BALANCE	(0x1<<12) /* Default */

drivers/gpu/drm/i915/intel_pm.c

@@ -3680,6 +3680,10 @@ static void gen7_setup_fixed_func_scheduler(struct drm_i915_private *dev_priv)
 	reg |= GEN7_FF_VS_SCHED_HW;
 	reg |= GEN7_FF_DS_SCHED_HW;
 
+	/* WaVSRefCountFullforceMissDisable */
+	if (IS_HASWELL(dev_priv->dev))
+		reg &= ~GEN7_FF_VS_REF_CNT_FFME;
+
 	I915_WRITE(GEN7_FF_THREAD_MODE, reg);
 }