3 files changed, 15 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 53fc1b3f6770..db75bb924e48 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -161,14 +161,14 @@ static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
         return min(source_max, sink_max);
 }
 
-static int
+int
 intel_dp_link_required(int pixel_clock, int bpp)
 {
         /* pixel_clock is in kHz, divide bpp by 8 for bit to Byte conversion */
         return DIV_ROUND_UP(pixel_clock * bpp, 8);
 }
 
-static int
+int
 intel_dp_max_data_rate(int max_link_clock, int max_lanes)
 {
         /* max_link_clock is the link symbol clock (LS_Clk) in kHz and not the
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 1f98757f61e7..205fe4748ec5 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -350,7 +350,17 @@ static enum drm_mode_status
 intel_dp_mst_mode_valid(struct drm_connector *connector,
                         struct drm_display_mode *mode)
 {
+        struct intel_connector *intel_connector = to_intel_connector(connector);
+        struct intel_dp *intel_dp = intel_connector->mst_port;
         int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
+        int bpp = 24; /* MST uses fixed bpp */
+        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(mode->clock, bpp);
 
         /* TODO - validate mode against available PBN for link */
         if (mode->clock < 10000)
@@ -359,7 +369,7 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
         if (mode->flags & DRM_MODE_FLAG_DBLCLK)
                 return MODE_H_ILLEGAL;
 
-        if (mode->clock > max_dotclk)
+        if (mode_rate > max_rate || mode->clock > max_dotclk)
                 return MODE_CLOCK_HIGH;
 
         return MODE_OK;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1d126c29598f..fd77a3ba857b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1457,6 +1457,8 @@ bool intel_dp_read_dpcd(struct intel_dp *intel_dp);
 bool __intel_dp_read_desc(struct intel_dp *intel_dp,
                           struct intel_dp_desc *desc);
 bool intel_dp_read_desc(struct intel_dp *intel_dp);
+int intel_dp_link_required(int pixel_clock, int bpp);
+int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
 
 /* intel_dp_aux_backlight.c */
 int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);