--- /dev/null
+--- a/drivers/net/wireless/ath/ath9k/beacon.c
++++ b/drivers/net/wireless/ath/ath9k/beacon.c
+@@ -351,9 +351,7 @@ void ath_beacon_tasklet(unsigned long da
+ struct ath_buf *bf = NULL;
+ struct ieee80211_vif *vif;
+ int slot;
+- u32 bfaddr, bc = 0, tsftu;
+- u64 tsf;
+- u16 intval;
++ u32 bfaddr, bc = 0;
+
+ /*
+ * Check if the previous beacon has gone out. If
+@@ -388,17 +386,27 @@ void ath_beacon_tasklet(unsigned long da
+ * on the tsf to safeguard against missing an swba.
+ */
+
+- intval = cur_conf->beacon_interval ? : ATH_DEFAULT_BINTVAL;
+
+- tsf = ath9k_hw_gettsf64(ah);
+- tsf += TU_TO_USEC(ah->config.sw_beacon_response_time);
+- tsftu = TSF_TO_TU((tsf * ATH_BCBUF) >>32, tsf * ATH_BCBUF);
+- slot = (tsftu % (intval * ATH_BCBUF)) / intval;
+- vif = sc->beacon.bslot[slot];
++ if (ah->opmode == NL80211_IFTYPE_AP) {
++ u16 intval;
++ u32 tsftu;
++ u64 tsf;
++
++ intval = cur_conf->beacon_interval ? : ATH_DEFAULT_BINTVAL;
++ tsf = ath9k_hw_gettsf64(ah);
++ tsf += TU_TO_USEC(ah->config.sw_beacon_response_time);
++ tsftu = TSF_TO_TU((tsf * ATH_BCBUF) >>32, tsf * ATH_BCBUF);
++ slot = (tsftu % (intval * ATH_BCBUF)) / intval;
++ vif = sc->beacon.bslot[slot];
++
++ ath_dbg(common, ATH_DBG_BEACON,
++ "slot %d [tsf %llu tsftu %u intval %u] vif %p\n",
++ slot, tsf, tsftu / ATH_BCBUF, intval, vif);
++ } else {
++ slot = 0;
++ vif = sc->beacon.bslot[slot];
++ }
+
+- ath_dbg(common, ATH_DBG_BEACON,
+- "slot %d [tsf %llu tsftu %u intval %u] vif %p\n",
+- slot, tsf, tsftu / ATH_BCBUF, intval, vif);
+
+ bfaddr = 0;
+ if (vif) {