From a2068afd77dcde2c3cf274dc73b71b689c5fedc7 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Fri, 28 Feb 2014 18:08:23 +0000
Subject: [PATCH] ath9k: improve noise immunity behavior for older chipsets
(ar92xx and earlier), should improve stability
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
SVN-Revision: 39767
---
.../mac80211/patches/300-pending_work.patch | 116 ++++++++++++++++++
.../540-ath9k_reduce_ani_interval.patch | 2 +-
2 files changed, 117 insertions(+), 1 deletion(-)
diff --git a/package/kernel/mac80211/patches/300-pending_work.patch b/package/kernel/mac80211/patches/300-pending_work.patch
index e324d9f8c1..1a68845aae 100644
--- a/package/kernel/mac80211/patches/300-pending_work.patch
+++ b/package/kernel/mac80211/patches/300-pending_work.patch
@@ -1,3 +1,41 @@
+commit 1abdeca3c6fb9cf1f84f85e78ed8d1c33bd69db0
+Author: Felix Fietkau <nbd@openwrt.org>
+Date: Fri Feb 28 18:52:56 2014 +0100
+
+ ath9k_hw: tweak noise immunity thresholds for older chipsets
+
+ Older chipsets are more sensitive to high PHY error counts, and the
+ current noise immunity thresholds were based on tests run at QCA with
+ newer chipsets.
+
+ This patch brings back the values from the old ANI implementation for
+ old chipsets, and it also disables weak signal detection on an earlier
+ noise immunity level, to improve overall radio stability on affected
+ devices.
+
+ Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+
+commit 431e506da5953adc3b65af25f4b90873d528c115
+Author: Felix Fietkau <nbd@openwrt.org>
+Date: Fri Feb 28 18:44:13 2014 +0100
+
+ ath9k_hw: toggle weak signal detection in AP mode on older chipsets
+
+ The commit 80b4205b "ath9k: Fix OFDM weak signal detection for AP mode"
+ prevented weak signal detection changes from taking effect in AP mode on
+ all chipsets, claiming it is "not allowed".
+
+ The main reason for not disabling weak signal detection in AP mode is
+ that typically beacon RSSI is used to track whether it is needed to
+ boost range, and this is unavailable in AP mode for obvious reasons.
+
+ The problem with not disabling weak signal detection is that older
+ chipsets are very sensitive to high PHY error counts. When faced with
+ heavy noise, this can lead to an excessive amount of "Failed to stop
+ TX DMA" errors in the field.
+
+ Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+
commit 98d1a6c5b14688ed030e81b889f607be308e0df9
Author: Felix Fietkau <nbd@openwrt.org>
Date: Mon Feb 24 22:20:32 2014 +0100
@@ -3591,3 +3629,81 @@ Date: Thu Jan 23 20:06:34 2014 +0100
}
static void ath9k_rx_skb_postprocess(struct ath_common *common,
+--- a/drivers/net/wireless/ath/ath9k/ani.c
++++ b/drivers/net/wireless/ath/ath9k/ani.c
+@@ -176,16 +176,26 @@ static void ath9k_hw_set_ofdm_nil(struct
+ if (ah->opmode == NL80211_IFTYPE_STATION &&
+ BEACON_RSSI(ah) <= ATH9K_ANI_RSSI_THR_HIGH)
+ weak_sig = true;
+-
+ /*
+- * OFDM Weak signal detection is always enabled for AP mode.
++ * Newer chipsets are better at dealing with high PHY error counts -
++ * keep weak signal detection enabled when no RSSI threshold is
++ * available to determine if it is needed (mode != STA)
+ */
+- if (ah->opmode != NL80211_IFTYPE_AP &&
+- aniState->ofdmWeakSigDetect != weak_sig) {
+- ath9k_hw_ani_control(ah,
+- ATH9K_ANI_OFDM_WEAK_SIGNAL_DETECTION,
+- entry_ofdm->ofdm_weak_signal_on);
+- }
++ else if (AR_SREV_9300_20_OR_LATER(ah) &&
++ ah->opmode != NL80211_IFTYPE_STATION)
++ weak_sig = true;
++
++ /* Older chipsets are more sensitive to high PHY error counts */
++ else if (!AR_SREV_9300_20_OR_LATER(ah) &&
++ aniState->ofdmNoiseImmunityLevel >= 8)
++ weak_sig = false;
++
++ if (aniState->ofdmWeakSigDetect != weak_sig)
++ ath9k_hw_ani_control(ah, ATH9K_ANI_OFDM_WEAK_SIGNAL_DETECTION,
++ weak_sig);
++
++ if (!AR_SREV_9300_20_OR_LATER(ah))
++ return;
+
+ if (aniState->ofdmNoiseImmunityLevel >= ATH9K_ANI_OFDM_DEF_LEVEL) {
+ ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH;
+@@ -483,10 +493,17 @@ void ath9k_hw_ani_init(struct ath_hw *ah
+
+ ath_dbg(common, ANI, "Initialize ANI\n");
+
+- ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH;
+- ah->config.ofdm_trig_low = ATH9K_ANI_OFDM_TRIG_LOW;
+- ah->config.cck_trig_high = ATH9K_ANI_CCK_TRIG_HIGH;
+- ah->config.cck_trig_low = ATH9K_ANI_CCK_TRIG_LOW;
++ if (AR_SREV_9300_20_OR_LATER(ah)) {
++ ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH;
++ ah->config.ofdm_trig_low = ATH9K_ANI_OFDM_TRIG_LOW;
++ ah->config.cck_trig_high = ATH9K_ANI_CCK_TRIG_HIGH;
++ ah->config.cck_trig_low = ATH9K_ANI_CCK_TRIG_LOW;
++ } else {
++ ah->config.ofdm_trig_high = ATH9K_ANI_OFDM_TRIG_HIGH_OLD;
++ ah->config.ofdm_trig_low = ATH9K_ANI_OFDM_TRIG_LOW_OLD;
++ ah->config.cck_trig_high = ATH9K_ANI_CCK_TRIG_HIGH_OLD;
++ ah->config.cck_trig_low = ATH9K_ANI_CCK_TRIG_LOW_OLD;
++ }
+
+ ani->spurImmunityLevel = ATH9K_ANI_SPUR_IMMUNE_LVL;
+ ani->firstepLevel = ATH9K_ANI_FIRSTEP_LVL;
+--- a/drivers/net/wireless/ath/ath9k/ani.h
++++ b/drivers/net/wireless/ath/ath9k/ani.h
+@@ -22,12 +22,16 @@
+ /* units are errors per second */
+ #define ATH9K_ANI_OFDM_TRIG_HIGH 3500
+ #define ATH9K_ANI_OFDM_TRIG_HIGH_BELOW_INI 1000
++#define ATH9K_ANI_OFDM_TRIG_HIGH_OLD 500
+
+ #define ATH9K_ANI_OFDM_TRIG_LOW 400
+ #define ATH9K_ANI_OFDM_TRIG_LOW_ABOVE_INI 900
++#define ATH9K_ANI_OFDM_TRIG_LOW_OLD 200
+
+ #define ATH9K_ANI_CCK_TRIG_HIGH 600
++#define ATH9K_ANI_CCK_TRIG_HIGH_OLD 200
+ #define ATH9K_ANI_CCK_TRIG_LOW 300
++#define ATH9K_ANI_CCK_TRIG_LOW_OLD 100
+
+ #define ATH9K_ANI_SPUR_IMMUNE_LVL 3
+ #define ATH9K_ANI_FIRSTEP_LVL 2
diff --git a/package/kernel/mac80211/patches/540-ath9k_reduce_ani_interval.patch b/package/kernel/mac80211/patches/540-ath9k_reduce_ani_interval.patch
index 7c24f46f67..e899903478 100644
--- a/package/kernel/mac80211/patches/540-ath9k_reduce_ani_interval.patch
+++ b/package/kernel/mac80211/patches/540-ath9k_reduce_ani_interval.patch
@@ -1,6 +1,6 @@
--- a/drivers/net/wireless/ath/ath9k/ani.h
+++ b/drivers/net/wireless/ath/ath9k/ani.h
-@@ -38,7 +38,7 @@
+@@ -42,7 +42,7 @@
#define ATH9K_ANI_PERIOD 300
/* in ms */
--
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