diff --git a/drivers/net/wireless/mediatek/mt7601u/phy.c b/drivers/net/wireless/mediatek/mt7601u/phy.c
index 9d2f9a776ef1..b804abd464ae 100644
--- a/drivers/net/wireless/mediatek/mt7601u/phy.c
+++ b/drivers/net/wireless/mediatek/mt7601u/phy.c
@@ -986,13 +986,15 @@ static void mt7601u_agc_tune(struct mt7601u_dev *dev)
 	 */
 	spin_lock_bh(&dev->con_mon_lock);
 	avg_rssi = ewma_rssi_read(&dev->avg_rssi);
-	WARN_ON_ONCE(avg_rssi == 0);
+	spin_unlock_bh(&dev->con_mon_lock);
+	if (avg_rssi == 0)
+		return;
+
 	avg_rssi = -avg_rssi;
 	if (avg_rssi <= -70)
 		val -= 0x20;
 	else if (avg_rssi <= -60)
 		val -= 0x10;
-	spin_unlock_bh(&dev->con_mon_lock);
 
 	if (val != mt7601u_bbp_rr(dev, 66))
 		mt7601u_bbp_wr(dev, 66, val);