1 files changed, 42 insertions, 13 deletions

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 65c1700f3e40..379a449a28a2 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -2339,7 +2339,7 @@ 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;
-	int old_ddps = 0, ret;
+	int ret;
 	u8 new_pdt = DP_PEER_DEVICE_NONE;
 	bool new_mcs = 0;
 	bool created = false, send_link_addr = false, changed = false;
@@ -2372,7 +2372,6 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
 		 */
 		drm_modeset_lock(&mgr->base.lock, NULL);
 
-		old_ddps = port->ddps;
 		changed = port->ddps != port_msg->ddps ||
 			(port->ddps &&
 			 (port->ldps != port_msg->legacy_device_plug_status ||
@@ -2407,15 +2406,13 @@ drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
 	 * Reprobe PBN caps on both hotplug, and when re-probing the link
 	 * for our parent mstb
 	 */
-	if (old_ddps != port->ddps || !created) {
-		if (port->ddps && !port->input) {
-			ret = drm_dp_send_enum_path_resources(mgr, mstb,
-							      port);
-			if (ret == 1)
-				changed = true;
-		} else {
-			port->full_pbn = 0;
-		}
+	if (port->ddps && !port->input) {
+		ret = drm_dp_send_enum_path_resources(mgr, mstb,
+						      port);
+		if (ret == 1)
+			changed = true;
+	} else {
+		port->full_pbn = 0;
 	}
 
 	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
@@ -2692,6 +2689,11 @@ static void drm_dp_mst_link_probe_work(struct work_struct *work)
 		drm_kms_helper_hotplug_event(dev);
 }
 
+static void drm_dp_mst_queue_probe_work(struct drm_dp_mst_topology_mgr *mgr)
+{
+	queue_work(system_long_wq, &mgr->work);
+}
+
 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
 				 u8 *guid)
 {
@@ -3685,7 +3687,7 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
 		/* Write reset payload */
 		drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
 
-		queue_work(system_long_wq, &mgr->work);
+		drm_dp_mst_queue_probe_work(mgr);
 
 		ret = 0;
 	} else {
@@ -3724,6 +3726,33 @@ drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
 }
 
 /**
+ * drm_dp_mst_topology_queue_probe - Queue a topology probe
+ * @mgr: manager to probe
+ *
+ * Queue a work to probe the MST topology. Driver's should call this only to
+ * sync the topology's HW->SW state after the MST link's parameters have
+ * changed in a way the state could've become out-of-sync. This is the case
+ * for instance when the link rate between the source and first downstream
+ * branch device has switched between UHBR and non-UHBR rates. Except of those
+ * cases - for instance when a sink gets plugged/unplugged to a port - the SW
+ * state will get updated automatically via MST UP message notifications.
+ */
+void drm_dp_mst_topology_queue_probe(struct drm_dp_mst_topology_mgr *mgr)
+{
+	mutex_lock(&mgr->lock);
+
+	if (drm_WARN_ON(mgr->dev, !mgr->mst_state || !mgr->mst_primary))
+		goto out_unlock;
+
+	drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
+	drm_dp_mst_queue_probe_work(mgr);
+
+out_unlock:
+	mutex_unlock(&mgr->lock);
+}
+EXPORT_SYMBOL(drm_dp_mst_topology_queue_probe);
+
+/**
  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
  * @mgr: manager to suspend
  *
@@ -3809,7 +3838,7 @@ int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
 	 * state of our in-memory topology back into sync with reality. So,
 	 * restart the probing process as if we're probing a new hub
 	 */
-	queue_work(system_long_wq, &mgr->work);
+	drm_dp_mst_queue_probe_work(mgr);
 	mutex_unlock(&mgr->lock);
 
 	if (sync) {