--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -505,7 +505,7 @@ static void ath_beacon_config_ap(struct 
 	/* NB: the beacon interval is kept internally in TU's */
 	intval = TU_TO_USEC(conf->beacon_interval);
 	intval /= ATH_BCBUF;    /* for staggered beacons */
-	nexttbtt = intval;
+	nexttbtt = roundup(ath9k_hw_gettsf32(ah) + TU_TO_USEC(FUDGE), intval);
 
 	/*
 	 * In AP mode we enable the beacon timers and SWBA interrupts to