--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -27,9 +27,9 @@
 #define HT_STF                  4
 #define HT_LTF(_ns)             (4 * (_ns))
 #define SYMBOL_TIME(_ns)        ((_ns) << 2) /* ns * 4 us */
-#define SYMBOL_TIME_HALFGI(_ns) (((_ns) * 18 + 4) / 5)  /* ns * 3.6 us */
+#define SYMBOL_TIME_HALFGI(_ns) (((_ns) * 18 + 4) / 6)  /* ns * 3.6 us */
 #define NUM_SYMBOLS_PER_USEC(_usec) (_usec >> 2)
-#define NUM_SYMBOLS_PER_USEC_HALFGI(_usec) (((_usec*5)-4)/18)
+#define NUM_SYMBOLS_PER_USEC_HALFGI(_usec) (((_usec*6)-4)/18)
 
 #define OFDM_SIFS_TIME    	    16