openwrtv4/package/mac80211/patches/580-mac80211_ignore_bad_signal_values.patch

--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -659,6 +659,8 @@ ieee80211_tx_info_clear_status(struct ie
  * @RX_FLAG_HT: HT MCS was used and rate_idx is MCS index
  * @RX_FLAG_40MHZ: HT40 (40 MHz) was used
  * @RX_FLAG_SHORT_GI: Short guard interval was used
+ * @RX_FLAG_NO_SIGNAL_VAL: The signal strength value is not present.
+ *	Valid only for data frames (mainly A-MPDU)
  */
 enum mac80211_rx_flags {
 	RX_FLAG_MMIC_ERROR	= 1<<0,
@@ -672,6 +674,7 @@ enum mac80211_rx_flags {
 	RX_FLAG_HT		= 1<<9,
 	RX_FLAG_40MHZ		= 1<<10,
 	RX_FLAG_SHORT_GI	= 1<<11,
+	RX_FLAG_NO_SIGNAL_VAL	= 1<<12,
 };
 
 /**
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -177,7 +177,8 @@ ieee80211_add_rx_radiotap_header(struct 
 	pos += 2;
 
 	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
-	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
+	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM &&
+	    !(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
 		*pos = status->signal;
 		rthdr->it_present |=
 			cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
@@ -1310,8 +1311,10 @@ ieee80211_rx_h_sta_process(struct ieee80
 
 	sta->rx_fragments++;
 	sta->rx_bytes += rx->skb->len;
-	sta->last_signal = status->signal;
-	ewma_add(&sta->avg_signal, -status->signal);
+	if (!(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
+		sta->last_signal = status->signal;
+		ewma_add(&sta->avg_signal, -status->signal);
+	}
 
 	if (status->chains) {
 		sta->chains = status->chains;