ath9k returns a wrong RSSI value for frames received in a 30ms time window after
a channel change. The correct value is typically 10dB below the returned value.
This was found with a Atheros AR9300 Rev:3 chip (WLE350NX / JWX6083 cards),
during offchannel scans.
Mark the signal value as invalid in this case.
Signed-off-by: Jean Pierre TOSONI <jp.tosoni@xxxxxxxxx>
---
.../a995-b-acksys-ath9k-wait-channel-change.patch | 39 ++++++++++++++++++++
1 files changed, 39 insertions(+), 0 deletions(-)
create mode 100644 package/kernel/mac80211/patches/a995-b-acksys-ath9k-wait-channel-change.patch
diff --git a/package/kernel/mac80211/patches/a995-b-acksys-ath9k-wait-channel-change.patch b/package/kernel/mac80211/patches/a995-b-acksys-ath9k-wait-channel-change.patch
new file mode 100644
index 0000000..d1e1146
--- /dev/null
+++ b/package/kernel/mac80211/patches/a995-b-acksys-ath9k-wait-channel-change.patch
@@ -0,0 +1,39 @@
+--- a/drivers/net/wireless/ath/ath9k/ani.c
++++ b/drivers/net/wireless/ath/ath9k/ani.c
+@@ -333,6 +333,7 @@ void ath9k_ani_reset(struct ath_hw *ah,
+ return;
+
+ BUG_ON(aniState == NULL);
++ ah->chan_stable_time = jiffies + (30*HZ)/1000; /* 30ms */
+ ah->stats.ast_ani_reset++;
+
+ ofdm_nil = max_t(int, ATH9K_ANI_OFDM_DEF_LEVEL,
+--- a/drivers/net/wireless/ath/ath9k/common.c
++++ b/drivers/net/wireless/ath/ath9k/common.c
+@@ -220,6 +220,16 @@ void ath9k_cmn_process_rssi(struct ath_c
+ int i, j;
+
+ /*
++ * RSSI is not available before 30ms after reset on ath9k.
++ */
++ if (time_before(jiffies, ah->chan_stable_time)) {
++ ath_dbg(common, ANY, "early frame rssi=%d\n",rx_stats->rs_rssi);
++ rxs->flag |= RX_FLAG_NO_SIGNAL_VAL;
++ return;
++ }
++ ah->chan_stable_time = jiffies; /* advance stable time to cop with jiffies wraparound */
++
++ /*
+ * RSSI is not available for subframes in an A-MPDU.
+ */
+ if (rx_stats->rs_moreaggr) {
+--- a/drivers/net/wireless/ath/ath9k/hw.h
++++ b/drivers/net/wireless/ath/ath9k/hw.h
+@@ -816,6 +816,7 @@ struct ath_hw {
+
+ bool reset_power_on;
+ bool htc_reset_init;
++ unsigned long chan_stable_time;
+
+ enum nl80211_iftype opmode;
+ enum ath9k_power_mode power_mode;
--
1.7.2.5
