iwl3945: 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.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlegacy/3945.c

@@ -331,6 +331,19 @@ il3945_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
+	 * il3945_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");
+	}
+
 	txq->time_stamp = jiffies;
 	info = IEEE80211_SKB_CB(txq->skbs[txq->q.read_ptr]);
 	ieee80211_tx_info_clear_status(info);
@@ -488,6 +501,11 @@ il3945_pass_packet_to_mac80211(struct il_priv *il, struct il_rx_buf *rxb,
 		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");
+	}
+
 	skb = dev_alloc_skb(128);
 	if (!skb) {
 		IL_ERR("dev_alloc_skb failed\n");