ath9k: Disable SWBA interrupt on remove_interface

while removing beaconing mode interface, SWBA interrupt
was never disabled when there are no other beaconing interfaces.

Cc: stable@kernel.org
Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/main.c

@@ -1519,6 +1519,7 @@ static void ath9k_remove_interface(struct ieee80211_hw *hw,
 	struct ath_softc *sc = aphy->sc;
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 	struct ath_vif *avp = (void *)vif->drv_priv;
+	bool bs_valid = false;
 	int i;
 
 	ath_print(common, ATH_DBG_CONFIG, "Detach Interface\n");
@@ -1547,7 +1548,15 @@ static void ath9k_remove_interface(struct ieee80211_hw *hw,
 			       "slot\n", __func__);
 			sc->beacon.bslot[i] = NULL;
 			sc->beacon.bslot_aphy[i] = NULL;
-		}
+		} else if (sc->beacon.bslot[i])
+			bs_valid = true;
+	}
+	if (!bs_valid && (sc->sc_ah->imask & ATH9K_INT_SWBA)) {
+		/* Disable SWBA interrupt */
+		sc->sc_ah->imask &= ~ATH9K_INT_SWBA;
+		ath9k_ps_wakeup(sc);
+		ath9k_hw_set_interrupts(sc->sc_ah, sc->sc_ah->imask);
+		ath9k_ps_restore(sc);
 	}
 
 	sc->nvifs--;