diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index ee28b372afa4..dffd80f31537 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1352,6 +1352,7 @@ static void drm_dp_free_mst_port(struct kref *kref)
 		container_of(kref, struct drm_dp_mst_port, malloc_kref);
 
 	drm_dp_mst_put_mstb_malloc(port->parent);
+	mutex_destroy(&port->lock);
 	kfree(port);
 }
 
@@ -1818,6 +1819,36 @@ static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
 	strlcat(proppath, temp, proppath_size);
 }
 
+static void
+drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
+			      struct drm_dp_mst_port *port)
+{
+	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
+	char proppath[255];
+	int ret;
+
+	build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
+	port->connector = mgr->cbs->add_connector(mgr, port, proppath);
+	if (!port->connector) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||
+	     port->pdt == DP_PEER_DEVICE_SST_SINK) &&
+	    port->port_num >= DP_MST_LOGICAL_PORT_0) {
+		port->cached_edid = drm_get_edid(port->connector,
+						 &port->aux.ddc);
+		drm_connector_set_tile_property(port->connector);
+	}
+
+	mgr->cbs->register_connector(port->connector);
+	return;
+
+error:
+	DRM_ERROR("Failed to create connector for port %p: %d\n", port, ret);
+}
+
 static void
 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
 				    struct drm_device *dev,
@@ -1825,8 +1856,12 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
 {
 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
 	struct drm_dp_mst_port *port;
-	bool created = false;
-	int old_ddps = 0;
+	struct drm_dp_mst_branch *child_mstb = NULL;
+	struct drm_connector *connector_to_destroy = NULL;
+	int old_ddps = 0, ret;
+	u8 new_pdt = DP_PEER_DEVICE_NONE;
+	bool created = false, send_link_addr = false,
+	     create_connector = false;
 
 	port = drm_dp_get_port(mstb, port_msg->port_number);
 	if (!port) {
@@ -1835,6 +1870,7 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
 			return;
 		kref_init(&port->topology_kref);
 		kref_init(&port->malloc_kref);
+		mutex_init(&port->lock);
 		port->parent = mstb;
 		port->port_num = port_msg->port_number;
 		port->mgr = mgr;
@@ -1848,11 +1884,17 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
 		drm_dp_mst_get_mstb_malloc(mstb);
 
 		created = true;
-	} else {
-		old_ddps = port->ddps;
 	}
 
+	mutex_lock(&port->lock);
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+
+	if (!created)
+		old_ddps = port->ddps;
+
 	port->input = port_msg->input_port;
+	if (!port->input)
+		new_pdt = port_msg->peer_device_type;
 	port->mcs = port_msg->mcs;
 	port->ddps = port_msg->ddps;
 	port->ldps = port_msg->legacy_device_plug_status;
@@ -1880,44 +1922,58 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
 		}
 	}
 
-	if (!port->input) {
-		int ret = drm_dp_port_set_pdt(port,
-					      port_msg->peer_device_type);
-		if (ret == 1) {
-			drm_dp_send_link_address(mgr, port->mstb);
-		} else if (ret < 0) {
-			DRM_ERROR("Failed to change PDT on port %p: %d\n",
-				  port, ret);
-			goto fail;
+	ret = drm_dp_port_set_pdt(port, new_pdt);
+	if (ret == 1) {
+		send_link_addr = true;
+	} else if (ret < 0) {
+		DRM_ERROR("Failed to change PDT on port %p: %d\n",
+			  port, ret);
+		goto fail_unlock;
+	}
+
+	if (send_link_addr) {
+		mutex_lock(&mgr->lock);
+		if (port->mstb) {
+			child_mstb = port->mstb;
+			drm_dp_mst_get_mstb_malloc(child_mstb);
 		}
+		mutex_unlock(&mgr->lock);
 	}
 
-	if (created && !port->input) {
-		char proppath[255];
+	/*
+	 * We unset port->connector before dropping connection_mutex so that
+	 * there's no chance any of the atomic MST helpers can accidentally
+	 * associate a to-be-destroyed connector with a port.
+	 */
+	if (port->connector && port->input) {
+		connector_to_destroy = port->connector;
+		port->connector = NULL;
+	} else if (!port->connector && !port->input) {
+		create_connector = true;
+	}
 
-		build_mst_prop_path(mstb, port->port_num, proppath,
-				    sizeof(proppath));
-		port->connector = (*mgr->cbs->add_connector)(mgr, port,
-							     proppath);
-		if (!port->connector)
-			goto fail;
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
 
-		if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||
-		     port->pdt == DP_PEER_DEVICE_SST_SINK) &&
-		    port->port_num >= DP_MST_LOGICAL_PORT_0) {
-			port->cached_edid = drm_get_edid(port->connector,
-							 &port->aux.ddc);
-			drm_connector_set_tile_property(port->connector);
-		}
+	if (connector_to_destroy)
+		mgr->cbs->destroy_connector(mgr, connector_to_destroy);
+	else if (create_connector)
+		drm_dp_mst_port_add_connector(mstb, port);
+
+	mutex_unlock(&port->lock);
 
-		(*mgr->cbs->register_connector)(port->connector);
+	if (send_link_addr && child_mstb) {
+		drm_dp_send_link_address(mgr, child_mstb);
+		drm_dp_mst_put_mstb_malloc(child_mstb);
 	}
 
 	/* put reference to this port */
 	drm_dp_mst_topology_put_port(port);
 	return;
 
-fail:
+fail_unlock:
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+	mutex_unlock(&port->lock);
+
 	/* Remove it from the port list */
 	mutex_lock(&mgr->lock);
 	list_del(&port->next);
@@ -1933,6 +1989,7 @@ static void
 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
 			    struct drm_dp_connection_status_notify *conn_stat)
 {
+	struct drm_device *dev = mstb->mgr->dev;
 	struct drm_dp_mst_port *port;
 	int old_ddps;
 	bool dowork = false;
@@ -1941,6 +1998,8 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
 	if (!port)
 		return;
 
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+
 	old_ddps = port->ddps;
 	port->mcs = conn_stat->message_capability_status;
 	port->ldps = conn_stat->legacy_device_plug_status;
@@ -1966,6 +2025,7 @@ drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
 		}
 	}
 
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
 	drm_dp_mst_topology_put_port(port);
 	if (dowork)
 		queue_work(system_long_wq, &mstb->mgr->work);
@@ -2058,28 +2118,34 @@ drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
 static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
 					       struct drm_dp_mst_branch *mstb)
 {
+	struct drm_device *dev = mgr->dev;
 	struct drm_dp_mst_port *port;
-	struct drm_dp_mst_branch *mstb_child;
+
 	if (!mstb->link_address_sent)
 		drm_dp_send_link_address(mgr, mstb);
 
 	list_for_each_entry(port, &mstb->ports, next) {
-		if (port->input)
-			continue;
+		struct drm_dp_mst_branch *mstb_child = NULL;
+
+		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 
-		if (!port->ddps)
+		if (port->input || !port->ddps) {
+			drm_modeset_unlock(&dev->mode_config.connection_mutex);
 			continue;
+		}
 
 		if (!port->available_pbn)
 			drm_dp_send_enum_path_resources(mgr, mstb, port);
 
-		if (port->mstb) {
+		if (port->mstb)
 			mstb_child = drm_dp_mst_topology_get_mstb_validated(
 			    mgr, port->mstb);
-			if (mstb_child) {
-				drm_dp_check_and_send_link_address(mgr, mstb_child);
-				drm_dp_mst_topology_put_mstb(mstb_child);
-			}
+
+		drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+		if (mstb_child) {
+			drm_dp_check_and_send_link_address(mgr, mstb_child);
+			drm_dp_mst_topology_put_mstb(mstb_child);
 		}
 	}
 }
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index ac1a68574a1a..aed68d7e6492 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -45,23 +45,34 @@ struct drm_dp_vcpi {
 /**
  * struct drm_dp_mst_port - MST port
  * @port_num: port number
- * @input: if this port is an input port.
- * @mcs: message capability status - DP 1.2 spec.
- * @ddps: DisplayPort Device Plug Status - DP 1.2
- * @pdt: Peer Device Type
- * @ldps: Legacy Device Plug Status
- * @dpcd_rev: DPCD revision of device on this port
- * @num_sdp_streams: Number of simultaneous streams
- * @num_sdp_stream_sinks: Number of stream sinks
- * @available_pbn: Available bandwidth for this port.
+ * @input: if this port is an input port. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @mcs: message capability status - DP 1.2 spec. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @ddps: DisplayPort Device Plug Status - DP 1.2. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @pdt: Peer Device Type. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @ldps: Legacy Device Plug Status. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @dpcd_rev: DPCD revision of device on this port. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @num_sdp_streams: Number of simultaneous streams. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @num_sdp_stream_sinks: Number of stream sinks. Protected by
+ * &drm_device.mode_config.connection_mutex.
+ * @available_pbn: Available bandwidth for this port. Protected by
+ * &drm_device.mode_config.connection_mutex.
  * @next: link to next port on this branch device
  * @mstb: branch device on this port, protected by
  * &drm_dp_mst_topology_mgr.lock
  * @aux: i2c aux transport to talk to device connected to this port, protected
- * by &drm_dp_mst_topology_mgr.lock
+ * by &drm_device.mode_config.connection_mutex.
  * @parent: branch device parent of this port
  * @vcpi: Virtual Channel Payload info for this port.
- * @connector: DRM connector this port is connected to.
+ * @connector: DRM connector this port is connected to. Protected by @lock.
+ * When there is already a connector registered for this port, this is also
+ * protected by &drm_device.mode_config.connection_mutex.
  * @mgr: topology manager this port lives under.
  *
  * This structure represents an MST port endpoint on a device somewhere
@@ -100,6 +111,12 @@ struct drm_dp_mst_port {
 	struct drm_connector *connector;
 	struct drm_dp_mst_topology_mgr *mgr;
 
+	/**
+	 * @lock: Protects @connector. If needed, this lock should be grabbed
+	 * before &drm_device.mode_config.connection_mutex.
+	 */
+	struct mutex lock;
+
 	/**
 	 * @cached_edid: for DP logical ports - make tiling work by ensuring
 	 * that the EDID for all connectors is read immediately.
