ath9k: fix dynack in IBSS mode

Currently, dynack was only tested upstream using AP/STA mode.
Testing it on IBSS, showed that late-ack detection was broken.

This is caused due to dynack using Association Request/Response
frames for late-ack detection, which IBSS does not use.
Also allowing Authentication frames here solves this.

A second issue also got fixed, which was also seen AP/STA mode:

When a station was added, the estimated value would be exponentially averaged
using 0 as a starting point.

This means that on larger distances, the ack timeout was still not high
enough before synchronizing would run out of late-ack's for estimation.

Fix this by using the initial estimated value as a baseline
and only start averaging in the following estimation rounds.

Test setup:
- 2x identical devices:  RB912UAG-5HPnD + 19dB sector
- IBSS
- 2x2 802.11an (ar9340), HT20, long GI
- RSSI's  -70 / -71
- Real distance: 23910 meter

Results (60s iperf runs):

Fixed coverage class 54 (up to 24300m):
* 21.5 Mbits/sec

Dynack:
* 28.9 Mbits/sec

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/ath/553-ath9k-dynack-use-authentication-messages-for-late-ac.patch b/package/kernel/mac80211/patches/ath/553-ath9k-dynack-use-authentication-messages-for-late-ac.patch
new file mode 100644
index 0000000000..831c534762
--- /dev/null
+++ b/package/kernel/mac80211/patches/ath/553-ath9k-dynack-use-authentication-messages-for-late-ac.patch
@@ -0,0 +1,27 @@
+From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
+Date: Fri, 2 Nov 2018 21:49:55 +0100
+Subject: [PATCH] ath9k: dynack: use authentication messages for 'late' ack
+
+In order to properly support dynack in ad-hoc mode running
+wpa_supplicant, take into account authentication frames for
+'late ack' detection. This patch has been tested on devices
+mounted on offshore high-voltage stations connected through
+~24Km link
+
+Reported-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
+Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
+Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
+---
+
+--- a/drivers/net/wireless/ath/ath9k/dynack.c
++++ b/drivers/net/wireless/ath/ath9k/dynack.c
+@@ -187,7 +187,8 @@ void ath_dynack_sample_tx_ts(struct ath_
+ 	/* late ACK */
+ 	if (ts->ts_status & ATH9K_TXERR_XRETRY) {
+ 		if (ieee80211_is_assoc_req(hdr->frame_control) ||
+-		    ieee80211_is_assoc_resp(hdr->frame_control)) {
++		    ieee80211_is_assoc_resp(hdr->frame_control) ||
++		    ieee80211_is_auth(hdr->frame_control)) {
+ 			ath_dbg(common, DYNACK, "late ack\n");
+ 			ath9k_hw_setslottime(ah, (LATEACK_TO - 3) / 2);
+ 			ath9k_hw_set_ack_timeout(ah, LATEACK_TO);