drm/i915: Fix max link rate in intel_dp_mode_valid()

Consider the link rates reported by the sink via
DP_SUPPORTED_LINK_RATES when checking modes against the max link
rate.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Sonika Jindal <sonika.jindal@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -206,7 +206,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
 		target_clock = fixed_mode->clock;
 	}
 
-	max_link_clock = drm_dp_bw_code_to_link_rate(intel_dp_max_link_bw(intel_dp));
+	max_link_clock = intel_dp_max_link_rate(intel_dp);
 	max_lanes = intel_dp_max_lane_count(intel_dp);
 
 	max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
@@ -1242,6 +1242,19 @@ static int rate_to_index(int find, const int *rates)
 	return i;
 }
 
+int
+intel_dp_max_link_rate(struct intel_dp *intel_dp)
+{
+	int rates[DP_MAX_SUPPORTED_RATES] = {};
+	int len;
+
+	len = intel_supported_rates(intel_dp, rates);
+	if (WARN_ON(len <= 0))
+		return 162000;
+
+	return rates[rate_to_index(0, rates) - 1];
+}
+
 bool
 intel_dp_compute_config(struct intel_encoder *encoder,
 			struct intel_crtc_state *pipe_config)

drivers/gpu/drm/i915/intel_drv.h

@@ -1062,6 +1062,7 @@ void intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *co
 void intel_dp_mst_suspend(struct drm_device *dev);
 void intel_dp_mst_resume(struct drm_device *dev);
 int intel_dp_max_link_bw(struct intel_dp *intel_dp);
+int intel_dp_max_link_rate(struct intel_dp *intel_dp);
 void intel_dp_hot_plug(struct intel_encoder *intel_encoder);
 void vlv_power_sequencer_reset(struct drm_i915_private *dev_priv);
 uint32_t intel_dp_pack_aux(const uint8_t *src, int src_bytes);