ath9k: fix handling of tx headroom for padding

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

Backport of r47042

git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@47044 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 22 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/397-ath9k-declare-required-extra-tx-headroom.patch b/package/kernel/mac80211/patches/397-ath9k-declare-required-extra-tx-headroom.patch
new file mode 100644
index 0000000000..c420d20bae
--- /dev/null
+++ b/package/kernel/mac80211/patches/397-ath9k-declare-required-extra-tx-headroom.patch
@@ -0,0 +1,22 @@
+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
+@@ -867,6 +867,7 @@ 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;