drm/i915/skl: Implement WaDisablePowerCompilerClockGating

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Nick Hoath <nicholas.hoath@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -5258,6 +5258,7 @@ enum skl_disp_power_wells {
 
 #define HIZ_CHICKEN					0x7018
 # define CHV_HZ_8X8_MODE_IN_1X				(1<<15)
+# define BDW_HIZ_POWER_COMPILER_CLOCK_GATING_DISABLE	(1<<3)
 
 #define GEN9_SLICE_COMMON_ECO_CHICKEN0		0x7308
 #define  DISABLE_PIXEL_MASK_CAMMING		(1<<14)

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -1004,8 +1004,16 @@ static int gen9_init_workarounds(struct intel_engine_cs *ring)
 
 static int skl_init_workarounds(struct intel_engine_cs *ring)
 {
+	struct drm_device *dev = ring->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
 	gen9_init_workarounds(ring);
 
+	/* WaDisablePowerCompilerClockGating:skl */
+	if (INTEL_REVID(dev) == SKL_REVID_B0)
+		WA_SET_BIT_MASKED(HIZ_CHICKEN,
+				  BDW_HIZ_POWER_COMPILER_CLOCK_GATING_DISABLE);
+
 	return 0;
 }