diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index bdc19b04b2c10..a2d91a4997001 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -639,39 +639,60 @@ static int intel_dp_mst_get_modes(struct drm_connector *connector)
 	return intel_dp_mst_get_ddc_modes(connector);
 }
 
-static enum drm_mode_status
-intel_dp_mst_mode_valid(struct drm_connector *connector,
-			struct drm_display_mode *mode)
+static int
+intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
+			    struct drm_display_mode *mode,
+			    struct drm_modeset_acquire_ctx *ctx,
+			    enum drm_mode_status *status)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	struct intel_connector *intel_connector = to_intel_connector(connector);
 	struct intel_dp *intel_dp = intel_connector->mst_port;
+	struct drm_dp_mst_topology_mgr *mgr = &intel_dp->mst_mgr;
+	struct drm_dp_mst_port *port = intel_connector->port;
+	const int min_bpp = 18;
 	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
 	int max_rate, mode_rate, max_lanes, max_link_clock;
+	int ret;
 
-	if (drm_connector_is_unregistered(connector))
-		return MODE_ERROR;
+	if (drm_connector_is_unregistered(connector)) {
+		*status = MODE_ERROR;
+		return 0;
+	}
 
-	if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
-		return MODE_NO_DBLESCAN;
+	if (mode->flags & DRM_MODE_FLAG_DBLSCAN) {
+		*status = MODE_NO_DBLESCAN;
+		return 0;
+	}
 
 	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);
-	mode_rate = intel_dp_link_required(mode->clock, 18);
+	mode_rate = intel_dp_link_required(mode->clock, min_bpp);
 
-	/* TODO - validate mode against available PBN for link */
-	if (mode->clock < 10000)
-		return MODE_CLOCK_LOW;
+	ret = drm_modeset_lock(&mgr->base.lock, ctx);
+	if (ret)
+		return ret;
 
-	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
-		return MODE_H_ILLEGAL;
+	if (mode_rate > max_rate || mode->clock > max_dotclk ||
+	    drm_dp_calc_pbn_mode(mode->clock, min_bpp, false) > port->full_pbn) {
+		*status = MODE_CLOCK_HIGH;
+		return 0;
+	}
+
+	if (mode->clock < 10000) {
+		*status = MODE_CLOCK_LOW;
+		return 0;
+	}
 
-	if (mode_rate > max_rate || mode->clock > max_dotclk)
-		return MODE_CLOCK_HIGH;
+	if (mode->flags & DRM_MODE_FLAG_DBLCLK) {
+		*status = MODE_H_ILLEGAL;
+		return 0;
+	}
 
-	return intel_mode_valid_max_plane_size(dev_priv, mode);
+	*status = intel_mode_valid_max_plane_size(dev_priv, mode);
+	return 0;
 }
 
 static struct drm_encoder *intel_mst_atomic_best_encoder(struct drm_connector *connector,
@@ -700,7 +721,7 @@ intel_dp_mst_detect(struct drm_connector *connector,
 
 static const struct drm_connector_helper_funcs intel_dp_mst_connector_helper_funcs = {
 	.get_modes = intel_dp_mst_get_modes,
-	.mode_valid = intel_dp_mst_mode_valid,
+	.mode_valid_ctx = intel_dp_mst_mode_valid_ctx,
 	.atomic_best_encoder = intel_mst_atomic_best_encoder,
 	.atomic_check = intel_dp_mst_atomic_check,
 	.detect_ctx = intel_dp_mst_detect,