--- /dev/null
+--- a/drivers/net/wireless/ath/ath9k/hw.c
++++ b/drivers/net/wireless/ath/ath9k/hw.c
+@@ -1006,16 +1006,26 @@ 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;
--- /dev/null
+--- a/drivers/net/wireless/ath/ath9k/hw.c
++++ b/drivers/net/wireless/ath/ath9k/hw.c
+@@ -1007,31 +1007,35 @@ void ath9k_hw_init_global_settings(struc
+ if (IS_CHAN_HALF_RATE(chan)) {
+ eifs = 175;
+
+- if (!AR_SREV_9300_20_OR_LATER(ah))
++ if (!AR_SREV_9300_20_OR_LATER(ah)) {
+ rx_lat = 10;
+- else
++ sifstime = 8;
++ } else {
+ rx_lat *= 2;
++ sifstime = 32;
++ }
+
+ tx_lat *= 2;
+ if (IS_CHAN_A_FAST_CLOCK(ah, chan))
+ tx_lat += 11;
+
+ slottime = 13;
+- sifstime = 32;
+ } else if (IS_CHAN_QUARTER_RATE(chan)) {
+ eifs = 340;
+
+- if (!AR_SREV_9300_20_OR_LATER(ah))
++ if (!AR_SREV_9300_20_OR_LATER(ah)) {
+ rx_lat = 20;
+- else
++ sifstime = 8;
++ } else {
+ rx_lat = (rx_lat * 4) - 1;
++ sifstime = 64;
++ }
+
+ tx_lat *= 4;
+ if (IS_CHAN_A_FAST_CLOCK(ah, chan))
+ tx_lat += 22;
+
+ slottime = 21;
+- sifstime = 64;
+ } else {
+ if (AR_SREV_9287(ah) && AR_SREV_9287_13_OR_LATER(ah)) {
+ eifs = AR_D_GBL_IFS_EIFS_ASYNC_FIFO;