Index: if_ath_tx.c
===================================================================
--- if_ath_tx.c	(revision 219980)
+++ if_ath_tx.c	(working copy)
@@ -703,6 +703,24 @@
 	}
 
 	/*
+	 * If 11n protection is enabled and it's a HT frame,
+	 * enable RTS.
+	 *
+	 * XXX ic_htprotmode or ic_curhtprotmode?
+	 * XXX should it_htprotmode only matter if ic_curhtprotmode 
+	 * XXX indicates it's not a HT pure environment?
+	 *
+	 * XXX Should NOACK frames be HT protected with CTS-to-self?
+	 */
+	if ((ic->ic_htprotmode == IEEE80211_PROT_RTSCTS) &&
+	    rt->info[rix].phy == IEEE80211_T_HT &&
+	    (flags & HAL_TXDESC_NOACK) == 0) {
+		cix = rt->info[sc->sc_protrix].controlRate;
+	    	flags |= HAL_TXDESC_RTSENA;
+		sc->sc_stats.ast_tx_htprotect++;
+	}
+
+	/*
 	 * Calculate duration.  This logically belongs in the 802.11
 	 * layer but it lacks sufficient information to calculate it.
 	 */