iwl4965: workaround for firmware frame tx rejection

Firmware can reject to transmit frame on passive channel, when it
did not yet received any frame with valid CRC on that channel.
Workaround this problem in the driver.
Tested-by: NJake Edge <jake@lwn.net>
Signed-off-by: NStanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlegacy/4965-mac.c

@@ -588,6 +588,11 @@ il4965_pass_packet_to_mac80211(struct il_priv *il, struct ieee80211_hdr *hdr,
 		return;
 	}
 
+	if (unlikely(test_bit(IL_STOP_REASON_PASSIVE, &il->stop_reason))) {
+		il_wake_queues_by_reason(il, IL_STOP_REASON_PASSIVE);
+		D_INFO("Woke queues - frame received on passive channel\n");
+	}
+
 	/* In case of HW accelerated crypto and bad decryption, drop */
 	if (!il->cfg->mod_params->sw_crypto &&
 	    il_set_decrypted_flag(il, hdr, ampdu_status, stats))
@@ -2806,6 +2811,19 @@ il4965_hdl_tx(struct il_priv *il, struct il_rx_buf *rxb)
 		return;
 	}
 
+	/*
+	 * Firmware will not transmit frame on passive channel, if it not yet
+	 * received some valid frame on that channel. When this error happen
+	 * we have to wait until firmware will unblock itself i.e. when we
+	 * note received beacon or other frame. We unblock queues in
+	 * il4965_pass_packet_to_mac80211 or in il_mac_bss_info_changed.
+	 */
+	if (unlikely((status & TX_STATUS_MSK) == TX_STATUS_FAIL_PASSIVE_NO_RX) &&
+	    il->iw_mode == NL80211_IFTYPE_STATION) {
+		il_stop_queues_by_reason(il, IL_STOP_REASON_PASSIVE);
+		D_INFO("Stopped queues - RX waiting on passive channel\n");
+	}
+
 	spin_lock_irqsave(&il->sta_lock, flags);
 	if (txq->sched_retry) {
 		const u32 scd_ssn = il4965_get_scd_ssn(tx_resp);

drivers/net/wireless/iwlegacy/common.c

@@ -5306,6 +5306,17 @@ il_mac_bss_info_changed(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	if (changes & BSS_CHANGED_BSSID) {
 		D_MAC80211("BSSID %pM\n", bss_conf->bssid);
 
+		/*
+		 * On passive channel we wait with blocked queues to see if
+		 * there is traffic on that channel. If no frame will be
+		 * received (what is very unlikely since scan detects AP on
+		 * that channel, but theoretically possible), mac80211 associate
+		 * procedure will time out and mac80211 will call us with NULL
+		 * bssid. We have to unblock queues on such condition.
+		 */
+		if (is_zero_ether_addr(bss_conf->bssid))
+			il_wake_queues_by_reason(il, IL_STOP_REASON_PASSIVE);
+
 		/*
 		 * If there is currently a HW scan going on in the background,
 		 * then we need to cancel it, otherwise sometimes we are not