ath9k: backport dynack improvements

Close cooperation with Lorenzo Bianconi resulted
in these patches which fix all remaining seen issues
when using dynack.

Fix link losses when:
- Late Ack's are not seen or not present
- switching from too low static coverage class to dynack on a live link

These are fixed by setting the Ack Timeout/Slottime to
the max possible value for the currently used channel width when
a new station has been discovered.

When traffic flows, dynack is able to adjust to optimal values
within a few packets received (typically < 1 second)

These changes have been thoroughly tested on ~60 offshore devices
all interconnected using mesh over IBSS and dynack enabled on all.

Distances between devices varied from <100m up to ~35km

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/ath/559-ath9k-dynack-properly-set-last-timeout-timestamp-in-.patch b/package/kernel/mac80211/patches/ath/559-ath9k-dynack-properly-set-last-timeout-timestamp-in-.patch
new file mode 100644
index 0000000000..9504af1419
--- /dev/null
+++ b/package/kernel/mac80211/patches/ath/559-ath9k-dynack-properly-set-last-timeout-timestamp-in-.patch
@@ -0,0 +1,32 @@
+From e5b56ce50eab31d24df6a70cf025db3acc4aa3ac Mon Sep 17 00:00:00 2001
+From: Lorenzo Bianconi <lorenzo@kernel.org>
+Date: Tue, 20 Aug 2019 18:20:20 +0200
+Subject: [PATCH 2/4] ath9k: dynack: properly set last timeout timestamp in
+ ath_dynack_reset
+
+Add compute timeout to last computation timestamp in
+ath_dynack_reset in order to not run ath_dynack_compute_ackto
+immediately
+
+Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
+Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
+---
+ drivers/net/wireless/ath/ath9k/dynack.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/net/wireless/ath/ath9k/dynack.c b/drivers/net/wireless/ath/ath9k/dynack.c
+index 38dbe25919f7..398ea872751f 100644
+--- a/drivers/net/wireless/ath/ath9k/dynack.c
++++ b/drivers/net/wireless/ath/ath9k/dynack.c
+@@ -338,7 +338,7 @@ void ath_dynack_reset(struct ath_hw *ah)
+ 	u32 ackto = 9 + 16 + 64;
+ 	struct ath_dynack *da = &ah->dynack;
+ 
+-	da->lto = jiffies;
++	da->lto = jiffies + COMPUTE_TO;
+ 	da->ackto = ackto;
+ 
+ 	da->st_rbf.t_rb = 0;
+-- 
+2.17.1
+