From: Ben Cahill <ben.m.cahill@xxxxxxxxx>
Replace overly "sticky" averaging filters for rssi, signal, noise ...
In old filter, once initial values were set, it took a large deviation (16)
in new input values in order to nudge the filter output. This made signal
quality displays appear frozen, with (probably) inaccurate data.
The new filter keeps high-precision (16x) running averages, then quantizes
them to create the output value. Each new input value nudges the running
average a bit, and displays appear reassuringly alive, with accurate data.
Update comments.
Signed-off-by: Ben Cahill <ben.m.cahill@xxxxxxxxx>
---
net/mac80211/ieee80211.c | 20 ++++++++++++++------
net/mac80211/ieee80211_sta.c | 7 +++++++
net/mac80211/sta_info.h | 9 ++++++---
3 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 873ccb0..b838d9c 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -3603,12 +3603,20 @@ ieee80211_rx_h_sta_process(struct ieee80211_txrx_data *rx)
sta->rx_fragments++;
sta->rx_bytes += rx->skb->len;
- sta->last_rssi = (sta->last_rssi * 15 +
- rx->u.rx.status->ssi) / 16;
- sta->last_signal = (sta->last_signal * 15 +
- rx->u.rx.status->signal) / 16;
- sta->last_noise = (sta->last_noise * 15 +
- rx->u.rx.status->noise) / 16;
+
+ /* Low pass filter: 15/16 current avg + new.
+ * Accumulated values here are 16x values sent from driver. */
+ sta->accum_rssi = sta->accum_rssi - (sta->accum_rssi >> 4) +
+ rx->u.rx.status->ssi;
+ sta->accum_signal = sta->accum_signal - (sta->accum_signal >> 4) +
+ rx->u.rx.status->signal;
+ sta->accum_noise = sta->accum_noise - (sta->accum_noise >> 4) +
+ rx->u.rx.status->noise;
+
+ /* Quantize the averages (divide by 16) */
+ sta->last_rssi = sta->accum_rssi >> 4;
+ sta->last_signal = sta->accum_signal >> 4;
+ sta->last_noise = sta->accum_noise >> 4;
if (!(rx->fc & IEEE80211_FCTL_MOREFRAGS)) {
/* Change STA power saving mode only in the end of a frame
diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index b003912..5986183 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -1223,9 +1223,16 @@ static void ieee80211_rx_mgmt_assoc_resp(struct net_device *dev,
}
bss = ieee80211_rx_bss_get(dev, ifsta->bssid);
if (bss) {
+ /* Init signal values from beacon or probe response. */
sta->last_rssi = bss->rssi;
sta->last_signal = bss->signal;
sta->last_noise = bss->noise;
+
+ /* Init averaging filter accumulators to 16x values. */
+ sta->accum_rssi = bss->rssi << 4;
+ sta->accum_signal = bss->signal << 4;
+ sta->accum_noise = bss->noise << 4;
+
ieee80211_rx_bss_put(dev, bss);
}
}
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 6a067a0..0ee9212 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -83,9 +83,12 @@ struct sta_info {
unsigned long rx_fragments; /* number of received MPDUs */
unsigned long rx_dropped; /* number of dropped MPDUs from this STA */
- int last_rssi; /* RSSI of last received frame from this STA */
- int last_signal; /* signal of last received frame from this STA */
- int last_noise; /* noise of last received frame from this STA */
+ int accum_rssi; /* hi-precision running average (rssi * 16) */
+ int accum_signal; /* hi-precision average (signal-quality * 16) */
+ int accum_noise; /* hi-precision running average (noise * 16) */
+ int last_rssi; /* average RSSI of recent frames from this STA */
+ int last_signal; /* average sig-qual of recent frames from this STA */
+ int last_noise; /* average noise of recent frames from this STA */
int last_ack_rssi[3]; /* RSSI of last received ACKs from this STA */
unsigned long last_ack;
int channel_use;
--
1.5.2
-
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