--- a/drivers/net/wireless/ath/ath5k/mac80211-ops.c
+++ b/drivers/net/wireless/ath/ath5k/mac80211-ops.c
@@ -95,13 +95,8 @@ ath5k_add_interface(struct ieee80211_hw 
 		goto end;
 	}
 
-	/* Don't allow other interfaces if one ad-hoc is configured.
-	 * TODO: Fix the problems with ad-hoc and multiple other interfaces.
-	 * We would need to operate the HW in ad-hoc mode to allow TSF updates
-	 * for the IBSS, but this breaks with additional AP or STA interfaces
-	 * at the moment. */
-	if (sc->num_adhoc_vifs ||
-	    (sc->nvifs && vif->type == NL80211_IFTYPE_ADHOC)) {
+	/* Don't allow more than one ad-hoc interface */
+	if (sc->num_adhoc_vifs && vif->type == NL80211_IFTYPE_ADHOC) {
 		ATH5K_ERR(sc, "Only one single ad-hoc interface is allowed.\n");
 		ret = -ELNRNG;
 		goto end;
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -1883,7 +1883,7 @@ ath5k_beacon_send(struct ath5k_softc *sc
 		sc->bmisscount = 0;
 	}
 
-	if ((sc->opmode == NL80211_IFTYPE_AP && sc->num_ap_vifs > 1) ||
+	if ((sc->opmode == NL80211_IFTYPE_AP && sc->num_ap_vifs + sc->num_adhoc_vifs > 1) ||
 			sc->opmode == NL80211_IFTYPE_MESH_POINT) {
 		u64 tsf = ath5k_hw_get_tsf64(ah);
 		u32 tsftu = TSF_TO_TU(tsf);
@@ -1961,7 +1961,7 @@ ath5k_beacon_update_timers(struct ath5k_
 	u64 hw_tsf;
 
 	intval = sc->bintval & AR5K_BEACON_PERIOD;
-	if (sc->opmode == NL80211_IFTYPE_AP && sc->num_ap_vifs > 1) {
+	if (sc->opmode == NL80211_IFTYPE_AP && sc->num_ap_vifs + sc->num_adhoc_vifs > 1) {
 		intval /= ATH_BCBUF;	/* staggered multi-bss beacons */
 		if (intval < 15)
 			ATH5K_WARN(sc, "intval %u is too low, min 15\n",