mac80211: configure 11b/g channel access rules for legacy APs

For each EDCA TX queue change default settings (in STA mode) to conform
old 802.11b/g channel access rules. This is needed for drivers that do
not have QoS enable/disable "switch" (like rt2x00) to make them work
properly with legacy APs.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/util.c

@@ -804,7 +804,7 @@ void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata,
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_tx_queue_params qparam;
 	int ac;
-	bool use_11b;
+	bool use_11b, enable_qos;
 	int aCWmin, aCWmax;
 
 	if (!local->ops->conf_tx)
@@ -818,6 +818,13 @@ void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata,
 	use_11b = (local->hw.conf.channel->band == IEEE80211_BAND_2GHZ) &&
 		 !(sdata->flags & IEEE80211_SDATA_OPERATING_GMODE);
 
+	/*
+	 * By default disable QoS in STA mode for old access points, which do
+	 * not support 802.11e. New APs will provide proper queue parameters,
+	 * that we will configure later.
+	 */
+	enable_qos = (sdata->vif.type != NL80211_IFTYPE_STATION);
+
 	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
 		/* Set defaults according to 802.11-2007 Table 7-37 */
 		aCWmax = 1023;
@@ -826,6 +833,7 @@ void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata,
 		else
 			aCWmin = 15;
 
+		if (enable_qos) {
 			switch (ac) {
 			case IEEE80211_AC_BK:
 				qparam.cw_max = aCWmax;
@@ -833,7 +841,8 @@ void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata,
 				qparam.txop = 0;
 				qparam.aifs = 7;
 				break;
-		default: /* never happens but let's not leave undefined */
+			/* never happens but let's not leave undefined */
+			default:
 			case IEEE80211_AC_BE:
 				qparam.cw_max = aCWmax;
 				qparam.cw_min = aCWmin;
@@ -859,6 +868,13 @@ void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata,
 				qparam.aifs = 2;
 				break;
 			}
+		} else {
+			/* Confiure old 802.11b/g medium access rules. */
+			qparam.cw_max = aCWmax;
+			qparam.cw_min = aCWmin;
+			qparam.txop = 0;
+			qparam.aifs = 2;
+		}
 
 		qparam.uapsd = false;
 
@@ -866,12 +882,8 @@ void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata,
 		drv_conf_tx(local, sdata, ac, &qparam);
 	}
 
-	/* after reinitialize QoS TX queues setting to default,
-	 * disable QoS at all */
-
 	if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
-		sdata->vif.bss_conf.qos =
-			sdata->vif.type != NL80211_IFTYPE_STATION;
+		sdata->vif.bss_conf.qos = enable_qos;
 		if (bss_notify)
 			ieee80211_bss_info_change_notify(sdata,
 							 BSS_CHANGED_QOS);