diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
old mode 100644
new mode 100755
index 6efdba4..9f72512
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -42,7 +42,7 @@
  * drm_debug: Enable debug output.
  * Bitmask of DRM_UT_x. See include/drm/drmP.h for details.
  */
-unsigned int drm_debug = 0;
+unsigned int drm_debug = 0xe;
 EXPORT_SYMBOL(drm_debug);
 
 MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl");
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
old mode 100644
new mode 100755
index 3ffbd69..7f07034
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -331,11 +331,38 @@ static int intel_dp_mst_get_modes(struct drm_connector *connector)
 	return intel_dp_mst_get_ddc_modes(connector);
 }
 
+static int
+intel_dp_link_required(int pixel_clock, int bpp)
+{
+	return (pixel_clock * bpp + 9) / 10;
+}
+
+static int
+intel_dp_max_data_rate(int max_link_clock, int max_lanes)
+{
+	return (max_link_clock * max_lanes * 8) / 10;
+}
 static enum drm_mode_status
 intel_dp_mst_mode_valid(struct drm_connector *connector,
 			struct drm_display_mode *mode)
 {
 	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct intel_dp *intel_dp = intel_connector->mst_port;
+	int target_clock = mode->clock;
+	int max_rate, mode_rate, max_lanes, max_link_clock;
+
+	max_link_clock = intel_dp_max_link_rate(intel_dp);
+	max_lanes =  drm_dp_max_lane_count(intel_dp->dpcd);
+
+	max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
+	mode_rate = intel_dp_link_required(target_clock, 18);
+
+	DRM_DEBUG_KMS("%s %d %d mode_rate %d max_rate %d \n",mode->name, mode->vrefresh, mode->clock,mode_rate, max_rate);
+	DRM_DEBUG_KMS("target_clock %d max_dotclk %d\n",target_clock, max_dotclk);
+
+	if (mode_rate > max_rate || target_clock > max_dotclk)
+		return MODE_CLOCK_HIGH;
 
 	/* TODO - validate mode against available PBN for link */
 	if (mode->clock < 10000)
@@ -344,9 +371,6 @@ static int intel_dp_mst_get_modes(struct drm_connector *connector)
 	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
 		return MODE_H_ILLEGAL;
 
-	if (mode->clock > max_dotclk)
-		return MODE_CLOCK_HIGH;
-
 	return MODE_OK;
 }