--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1211,6 +1211,7 @@ void ath9k_hw_init_global_settings(struc
 {
 	struct ieee80211_conf *conf = &ath9k_hw_common(ah)->hw->conf;
 	int acktimeout;
+	int slottime;
 	int sifstime;
 
 	ath_print(ath9k_hw_common(ah), ATH_DBG_RESET, "ah->misc_mode 0x%x\n",
@@ -1225,8 +1226,10 @@ void ath9k_hw_init_global_settings(struc
 	else
 		sifstime = 10;
 
-	acktimeout = ah->slottime + sifstime;
-	ath9k_hw_setslottime(ah, ah->slottime);
+	/* As defined by IEEE 802.11-2007 17.3.8.6 */
+	slottime = ah->slottime + 3 * ah->coverage_class;
+	acktimeout = slottime + sifstime;
+	ath9k_hw_setslottime(ah, slottime);
 	ath9k_hw_set_ack_timeout(ah, acktimeout);
 	ath9k_hw_set_cts_timeout(ah, acktimeout);
 	if (ah->globaltxtimeout != (u32) -1)
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -551,6 +551,7 @@ struct ath_hw {
 	u32 *bank6Temp;
 
 	int16_t txpower_indexoffset;
+	int coverage_class;
 	u32 beacon_interval;
 	u32 slottime;
 	u32 globaltxtimeout;
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -2015,6 +2015,18 @@ static void ath9k_sw_scan_complete(struc
 	mutex_unlock(&sc->mutex);
 }
 
+static void ath9k_set_coverage_class(struct ieee80211_hw *hw, u8 coverage_class)
+{
+	struct ath_wiphy *aphy = hw->priv;
+	struct ath_softc *sc = aphy->sc;
+	struct ath_hw *ah = sc->sc_ah;
+
+	mutex_lock(&sc->mutex);
+	ah->coverage_class = coverage_class;
+	ath9k_hw_init_global_settings(ah);
+	mutex_unlock(&sc->mutex);
+}
+
 struct ieee80211_ops ath9k_ops = {
 	.tx 		    = ath9k_tx,
 	.start 		    = ath9k_start,
@@ -2034,4 +2046,5 @@ struct ieee80211_ops ath9k_ops = {
 	.sw_scan_start      = ath9k_sw_scan_start,
 	.sw_scan_complete   = ath9k_sw_scan_complete,
 	.rfkill_poll        = ath9k_rfkill_poll_state,
+	.set_coverage_class = ath9k_set_coverage_class,
 };