drm/i915/bxt: WaGsvDisableTurbo

Disable Turbo on steppings prior to B0 on BXT due to hangs seen during GT CPD exit.

Change-Id: I50c5c03f59f5ba092db19e17234951d89db42c6c
Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Reviewed by: Alex Dai <yu.dai@intel.com>.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -4487,6 +4487,10 @@ static void gen6_set_rps(struct drm_device *dev, u8 val)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
+	/* WaGsvDisableTurbo: Workaround to disable turbo on BXT A* */
+	if (IS_BROXTON(dev) && (INTEL_REVID(dev) < BXT_REVID_B0))
+		return;
+
 	WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
 	WARN_ON(val > dev_priv->rps.max_freq);
 	WARN_ON(val < dev_priv->rps.min_freq);
@@ -4807,6 +4811,12 @@ static void gen9_enable_rps(struct drm_device *dev)
 
 	gen6_init_rps_frequencies(dev);
 
+	/* WaGsvDisableTurbo: Workaround to disable turbo on BXT A* */
+	if (IS_BROXTON(dev) && (INTEL_REVID(dev) < BXT_REVID_B0)) {
+		intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+		return;
+	}
+
 	/* Program defaults and thresholds for RPS*/
 	I915_WRITE(GEN6_RC_VIDEO_FREQ,
 		GEN9_FREQUENCY(dev_priv->rps.rp1_freq));