diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 10eb6bae12d9..7f25da8444fe 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1100,7 +1100,8 @@ void ath9k_hw_init_global_settings(struct ath_hw *ah)
 	}
 
 	/* As defined by IEEE 802.11-2007 17.3.8.6 */
-	acktimeout = slottime + sifstime + 3 * ah->coverage_class + ack_offset;
+	slottime += 3 * ah->coverage_class;
+	acktimeout = slottime + sifstime + ack_offset;
 	ctstimeout = acktimeout;
 
 	/*