return 0;
 }
 
-int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
-                           struct drm_dp_mst_port *port,
-                           int id,
-                           int pbn)
+static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
+                                  struct drm_dp_mst_port *port,
+                                  int id,
+                                  int pbn)
 {
        struct drm_dp_sideband_msg_tx *txmsg;
        struct drm_dp_mst_branch *mstb;
        return 0;
 }
 
-int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
-                               struct drm_dp_mst_port *port,
-                               int id,
-                               struct drm_dp_payload *payload)
+static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
+                                      struct drm_dp_mst_port *port,
+                                      int id,
+                                      struct drm_dp_payload *payload)
 {
        int ret;
        ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
        return ret;
 }
 
-int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
-                                struct drm_dp_mst_port *port,
-                                int id,
-                                struct drm_dp_payload *payload)
+static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
+                                       struct drm_dp_mst_port *port,
+                                       int id,
+                                       struct drm_dp_payload *payload)
 {
        DRM_DEBUG_KMS("\n");
        /* its okay for these to fail */
        return 0;
 }
 
-int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
-                                int id,
-                                struct drm_dp_payload *payload)
+static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
+                                       int id,
+                                       struct drm_dp_payload *payload)
 {
        payload->payload_state = 0;
        return 0;