drm/i915/gen9: Add WaClearHIZ_WM_CHICKEN3 for bxt and glk

Factor in clear values wherever required while updating destination
min/max.

References: HSDES#1604444184
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Cc: mesa-dev@lists.freedesktop.org
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180510200708.18097-1-michel.thierry@intel.com
Cc: stable@vger.kernel.org

drivers/gpu/drm/i915/i915_reg.h

@@ -7259,6 +7259,9 @@ enum {
 #define SLICE_ECO_CHICKEN0			_MMIO(0x7308)
 #define   PIXEL_MASK_CAMMING_DISABLE		(1 << 14)
 
+#define GEN9_WM_CHICKEN3			_MMIO(0x5588)
+#define   GEN9_FACTOR_IN_CLR_VAL_HIZ		(1 << 9)
+
 /* WaCatErrorRejectionIssue */
 #define GEN7_SQ_CHICKEN_MBCUNIT_CONFIG		_MMIO(0x9030)
 #define  GEN7_SQ_CHICKEN_MBCUNIT_SQINTMOB	(1<<11)

drivers/gpu/drm/i915/intel_workarounds.c

@@ -270,6 +270,10 @@ static int gen9_ctx_workarounds_init(struct drm_i915_private *dev_priv)
 			    GEN9_PREEMPT_GPGPU_LEVEL_MASK,
 			    GEN9_PREEMPT_GPGPU_COMMAND_LEVEL);
 
+	/* WaClearHIZ_WM_CHICKEN3:bxt,glk */
+	if (IS_GEN9_LP(dev_priv))
+		WA_SET_BIT_MASKED(GEN9_WM_CHICKEN3, GEN9_FACTOR_IN_CLR_VAL_HIZ);
+
 	return 0;
 }