+From: Felix Fietkau <nbd@openwrt.org>
+Date: Thu, 24 Sep 2015 16:57:37 +0200
+Subject: [PATCH] ath9k: declare required extra tx headroom
+
+ath9k inserts padding between the 802.11 header and the data area (to
+align it). Since it didn't declare this extra required headroom, this
+led to some nasty issues like randomly dropped packets in some setups.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+---
+
+--- a/drivers/net/wireless/ath/ath9k/init.c
++++ b/drivers/net/wireless/ath/ath9k/init.c
+@@ -875,6 +875,7 @@ static void ath9k_set_hw_capab(struct at
+ hw->max_rate_tries = 10;
+ hw->sta_data_size = sizeof(struct ath_node);
+ hw->vif_data_size = sizeof(struct ath_vif);
++ hw->extra_tx_headroom = 4;
+
+ hw->wiphy->available_antennas_rx = BIT(ah->caps.max_rxchains) - 1;
+ hw->wiphy->available_antennas_tx = BIT(ah->caps.max_txchains) - 1;