openwrt/package/mac80211/patches/542-ath9k_fix_half_quarter_rx_latency.patch

--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -1005,16 +1005,26 @@ void ath9k_hw_init_global_settings(struc
 
 	if (IS_CHAN_HALF_RATE(chan)) {
 		eifs = 175;
-		rx_lat *= 2;
+
+		if (!AR_SREV_9300_20_OR_LATER(ah))
+			rx_lat = 10;
+		else
+			rx_lat *= 2;
+
 		tx_lat *= 2;
 		if (IS_CHAN_A_FAST_CLOCK(ah, chan))
-		    tx_lat += 11;
+			tx_lat += 11;
 
 		slottime = 13;
 		sifstime = 32;
 	} else if (IS_CHAN_QUARTER_RATE(chan)) {
 		eifs = 340;
-		rx_lat = (rx_lat * 4) - 1;
+
+		if (!AR_SREV_9300_20_OR_LATER(ah))
+			rx_lat = 20;
+		else
+			rx_lat = (rx_lat * 4) - 1;
+
 		tx_lat *= 4;
 		if (IS_CHAN_A_FAST_CLOCK(ah, chan))
 		    tx_lat += 22;