diff --git a/sys/dev/iwx/if_iwx.c b/sys/dev/iwx/if_iwx.c
--- a/sys/dev/iwx/if_iwx.c
+++ b/sys/dev/iwx/if_iwx.c
@@ -3429,6 +3429,14 @@
 		sc->sc_rx_ba_sessions--;
 }
 
+/**
+ * @brief Allocate an AMPDU / aggregation session for the given node and TID.
+ *
+ * This allocates a TX queue specifically for that TID.
+ *
+ * Note that this routine currently doesn't return any status/errors,
+ * so the caller can't know if the aggregation session was setup or not.
+ */
 static void
 iwx_sta_tx_agg_start(struct iwx_softc *sc, struct ieee80211_node *ni,
     uint8_t tid)
@@ -3502,6 +3510,14 @@
 	IWX_UNLOCK(sc);
 }
 
+/**
+ * @brief Task called to setup a deferred block-ack session.
+ *
+ * This sets up any/all pending blockack sessions as defined
+ * in sc->ba_tx.start_tidmask.
+ *
+ * Note: the call to iwx_sta_tx_agg_start() isn't being error checked.
+ */
 static void
 iwx_ba_tx_task(void *arg, int npending __unused)
 {
@@ -5627,7 +5643,6 @@
 	u_int hdrlen;
 	uint32_t rate_n_flags;
 	uint16_t num_tbs, flags, offload_assist = 0;
-	uint8_t type, subtype;
 	int i, totlen, err, pad, qid;
 #define IWM_MAX_SCATTER 20
 	bus_dma_segment_t *seg, segs[IWM_MAX_SCATTER];
@@ -5638,38 +5653,32 @@
 	IWX_ASSERT_LOCKED(sc);
 
 	wh = mtod(m, struct ieee80211_frame *);
-	type = wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK;
-	subtype = wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK;
 	hdrlen = ieee80211_anyhdrsize(wh);
 
+	/*
+	 * Note: we're currently putting all frames into one queue
+	 * except for AMPDU queues.  We should be able to choose
+	 * other WME queues but first we need to verify they've been
+	 * correctly setup for data.
+	 */
 	qid = sc->first_data_qid;
 
 	/* Put QoS frames on the data queue which maps to their TID. */
 	if (IEEE80211_QOS_HAS_SEQ(wh) && (sc->sc_flags & IWX_FLAG_AMPDUTX)) {
 		uint16_t qos = ieee80211_gettid(wh);
 		uint8_t tid = qos & IEEE80211_QOS_TID;
-#if 0
+		struct ieee80211_tx_ampdu *tap = &ni->ni_tx_ampdu[tid];
+
+
 		/*
-		 * XXX-THJ: TODO when we enable ba we need to manage the
-		 * mappings
+		 * Only QoS data goes into an A-MPDU queue;
+		 * don't add QoS null, the other data types, etc.
 		 */
-		struct ieee80211_tx_ba *ba;
-		ba = &ni->ni_tx_ba[tid];
-
-		if (!IEEE80211_IS_MULTICAST(wh->i_addr1) &&
-		    type == IEEE80211_FC0_TYPE_DATA &&
-		    subtype != IEEE80211_FC0_SUBTYPE_NODATA &&
-		    subtype != IEEE80211_FC0_SUBTYPE_BAR &&
-		    sc->aggqid[tid] != 0  /*&&
-		    ba->ba_state == IEEE80211_BA_AGREED*/) {
-			qid = sc->aggqid[tid];
-#else
-		if (!IEEE80211_IS_MULTICAST(wh->i_addr1) &&
-		    type == IEEE80211_FC0_TYPE_DATA &&
-		    subtype != IEEE80211_FC0_SUBTYPE_NODATA &&
+		if (IEEE80211_AMPDU_RUNNING(tap) &&
+		    IEEE80211_IS_QOSDATA(wh) &&
+		    !IEEE80211_IS_MULTICAST(wh->i_addr1) &&
 		    sc->aggqid[tid] != 0) {
 			qid = sc->aggqid[tid];
-#endif
 		}
 	}
 
@@ -10903,6 +10912,24 @@
 	return;
 }
 
+/**
+ * @brief Called by net80211 to request an AMPDU session be established.
+ *
+ * This is called by net80211 to see if an AMPDU session can be established.
+ * Unfortunately it's done via a firmware command, we can't block here,
+ * net80211 sends an action frame if we return a success code (1)
+ * so the only thing to do is to tell net80211 we succeeded.
+ *
+ * @param ni	ieee80211_node to establish AMPDU session for
+ * @param tap	pointer to the per-TID state struct
+ * @param dialogtoken	dialogtoken field from the BA request
+ * @param baparamset	baparamset field from the BA request
+ * @param batimeout	batimeout field from the BA request
+ *
+ * @returns 1 if the AMPDU request is successful and net80211 should send
+ *   the action frame response, 0 if error (and net80211 won't send
+ *   the action frame response.)
+ */
 static int
 iwx_addba_request(struct ieee80211_node *ni, struct ieee80211_tx_ampdu *tap,
     int dialogtoken, int baparamset, int batimeout)
@@ -10914,7 +10941,14 @@
 	DPRINTF(("%s: tid=%i\n", __func__, tid));
 	sc->ba_tx.start_tidmask |= (1 << tid);
 	taskqueue_enqueue(sc->sc_tq, &sc->ba_tx_task);
-	return 0;
+
+	/*
+	 * For now succeed and hand it back to net80211; later on it
+	 * would be better to defer completing or rejecting it based
+	 * on whether the AMPDU TX queue is created.
+	 */
+	return (sc->sc_addba_request(ni, tap, dialogtoken, baparamset,
+	    batimeout));
 }