--- zzzz-none-000/linux-3.10.107/drivers/uwb/beacon.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/uwb/beacon.c	2021-02-04 17:41:59.000000000 +0000
@@ -117,6 +117,7 @@
 	int result;
 	struct device *dev = &rc->uwb_dev.dev;
 
+	dev_dbg(dev, "%s: channel = %d\n", __func__, channel);
 	if (channel < 0)
 		channel = -1;
 	if (channel == -1)
@@ -124,8 +125,10 @@
 	else {
 		/* channel >= 0...dah */
 		result = uwb_rc_start_beacon(rc, bpst_offset, channel);
-		if (result < 0)
+		if (result < 0) {
+			dev_err(dev, "Cannot start beaconing: %d\n", result);
 			return result;
+		}
 		if (le16_to_cpu(rc->ies->wIELength) > 0) {
 			result = uwb_rc_set_ie(rc, rc->ies);
 			if (result < 0) {
@@ -184,7 +187,7 @@
 
 /* Find a beacon by dev addr in the cache */
 static
-struct uwb_beca_e *__uwb_beca_find_bymac(struct uwb_rc *rc, 
+struct uwb_beca_e *__uwb_beca_find_bymac(struct uwb_rc *rc,
 					 const struct uwb_mac_addr *mac_addr)
 {
 	struct uwb_beca_e *bce, *next;
@@ -394,7 +397,6 @@
 	struct uwb_rc_evt_beacon *be;
 	struct uwb_beacon_frame *bf;
 	struct uwb_beca_e *bce;
-	unsigned long last_ts;
 
 	rc = evt->rc;
 	be = container_of(evt->notif.rceb, struct uwb_rc_evt_beacon, rceb);
@@ -438,8 +440,6 @@
 	/* purge old beacon data */
 	kfree(bce->be);
 
-	last_ts = bce->ts_jiffies;
-
 	/* Update commonly used fields */
 	bce->ts_jiffies = evt->ts_jiffies;
 	bce->be = be;
@@ -515,13 +515,13 @@
 	}
 	bpsc = container_of(evt->notif.rceb, struct uwb_rc_evt_bp_slot_change, rceb);
 
-	mutex_lock(&rc->uwb_dev.mutex);
 	if (uwb_rc_evt_bp_slot_change_no_slot(bpsc)) {
-		dev_info(dev, "stopped beaconing: No free slots in BP\n");
+		dev_err(dev, "stopped beaconing: No free slots in BP\n");
+		mutex_lock(&rc->uwb_dev.mutex);
 		rc->beaconing = -1;
+		mutex_unlock(&rc->uwb_dev.mutex);
 	} else
 		rc->uwb_dev.beacon_slot = uwb_rc_evt_bp_slot_change_slot_num(bpsc);
-	mutex_unlock(&rc->uwb_dev.mutex);
 
 	return 0;
 }