drm/i915/kbl: Add WaDisableSDEUnitClockGating

Add this workaround until upto kbl revid B0.

References: HSD#1802092
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-10-git-send-email-mika.kuoppala@intel.com
(cherry picked from commit 9498dba7b4ffe40a1e2b23d7718b77e49841248f)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -6702,11 +6702,25 @@ static void lpt_suspend_hw(struct drm_device *dev)
 	}
 }
 
+static void kabylake_init_clock_gating(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	/* See Bspec note for PSR2_CTL bit 31, Wa#828:kbl */
+	I915_WRITE(CHICKEN_PAR1_1,
+		   I915_READ(CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);
+
+	/* WaDisableSDEUnitClockGating:kbl */
+	if (IS_KBL_REVID(dev_priv, 0, KBL_REVID_B0))
+		I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
+			   GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
+}
+
 static void skylake_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	/* See Bspec note for PSR2_CTL bit 31, Wa#828:skl,kbl */
+	/* See Bspec note for PSR2_CTL bit 31, Wa#828:skl */
 	I915_WRITE(CHICKEN_PAR1_1,
 		   I915_READ(CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);
 }
@@ -7178,7 +7192,7 @@ void intel_init_clock_gating_hooks(struct drm_i915_private *dev_priv)
 	if (IS_SKYLAKE(dev_priv))
 		dev_priv->display.init_clock_gating = skylake_init_clock_gating;
 	else if (IS_KABYLAKE(dev_priv))
-		dev_priv->display.init_clock_gating = skylake_init_clock_gating;
+		dev_priv->display.init_clock_gating = kabylake_init_clock_gating;
 	else if (IS_BROXTON(dev_priv))
 		dev_priv->display.init_clock_gating = bxt_init_clock_gating;
 	else if (IS_BROADWELL(dev_priv))