iwlwifi: Monitor and recover the aggregation TX flow failure

This change monitors the tx statistics to detect the drop in throughput.
When the throughput drops, the ratio of the actual_ack_count and the expected_
ack_count also drops.  At the same time, the aggregated ba_timeout (the number
of ba timeout retries) also rises.  If the actual_ack_count/expected_ack_count
ratio is 0 and the number of ba timeout retries rises to 16, no tx packets
(tcp, udp, or ping - icmp) can be delivered.  The driver recovers from this
situation by reseting the uCode firmware.  If the actual_ack_count/expected_
ack_count ratio drops below 50% (but not 0) and the aggregated ba_timeout
retries just exceed 5 (but not 16), then the driver can reset the radio to
bring the throughput up.

Signed-off-by: Trieu 'Andrew' Nguyen <trieux.t.nguyen@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 31b156d58d7f..4157c6c8645f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2941,10 +2941,21 @@ static int iwl_mac_ampdu_action(struct ieee80211_hw *hw,
                         return ret;
         case IEEE80211_AMPDU_TX_START:
                 IWL_DEBUG_HT(priv, "start Tx\n");
-                return iwl_tx_agg_start(priv, sta->addr, tid, ssn);
+                ret = iwl_tx_agg_start(priv, sta->addr, tid, ssn);
+                if (ret == 0) {
+                        priv->agg_tids_count++;
+                        IWL_DEBUG_HT(priv, "priv->agg_tids_count = %u\n",
+                                priv->agg_tids_count);
+                }
+                return ret;
         case IEEE80211_AMPDU_TX_STOP:
                 IWL_DEBUG_HT(priv, "stop Tx\n");
                 ret = iwl_tx_agg_stop(priv, sta->addr, tid);
+                if ((ret == 0) && (priv->agg_tids_count > 0)) {
+                        priv->agg_tids_count--;
+                        IWL_DEBUG_HT(priv, "priv->agg_tids_count = %u\n",
+                                priv->agg_tids_count);
+                }
                 if (test_bit(STATUS_EXIT_PENDING, &priv->status))
                         return 0;
                 else
@@ -3364,6 +3375,7 @@ static int iwl_init_drv(struct iwl_priv *priv)
         priv->iw_mode = NL80211_IFTYPE_STATION;
         priv->current_ht_config.smps = IEEE80211_SMPS_STATIC;
         priv->missed_beacon_threshold = IWL_MISSED_BEACON_THRESHOLD_DEF;
+        priv->agg_tids_count = 0;
 
         /* Choose which receivers/antennas to use */
         if (priv->cfg->ops->hcmd->set_rxon_chain)