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>

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 31b156d..4157c6c 100644 (file)
--- 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)

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 71cf155..f81317d 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1072,6 +1072,9 @@ struct iwl_priv {
        /* storing the jiffies when the plcp error rate is received */
        unsigned long plcp_jiffies;
 
+       /* reporting the number of tids has AGG on. 0 means no AGGREGATION */
+       u8 agg_tids_count;
+
        /* force reset */
        unsigned long last_force_reset_jiffies;
 

diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index aba8f4c..fed554a 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-rx.c
@@ -616,6 +616,11 @@ static void iwl_accumulative_statistics(struct iwl_priv *priv,
 
 #define REG_RECALIB_PERIOD (60)
 
+/* the threshold ratio of actual_ack_cnt to expected_ack_cnt in percent */
+#define ACK_CNT_RATIO (50)
+#define BA_TIMEOUT_CNT (5)
+#define BA_TIMEOUT_MAX (16)
+
 #define PLCP_MSG "plcp_err exceeded %u, %u, %u, %u, %u, %d, %u mSecs\n"
 void iwl_rx_statistics(struct iwl_priv *priv,
                              struct iwl_rx_mem_buffer *rxb)
@@ -625,6 +630,9 @@ void iwl_rx_statistics(struct iwl_priv *priv,
        int combined_plcp_delta;
        unsigned int plcp_msec;
        unsigned long plcp_received_jiffies;
+       int actual_ack_cnt_delta;
+       int expected_ack_cnt_delta;
+       int ba_timeout_delta;
 
        IWL_DEBUG_RX(priv, "Statistics notification received (%d vs %d).\n",
                     (int)sizeof(priv->statistics),
@@ -639,6 +647,44 @@ void iwl_rx_statistics(struct iwl_priv *priv,
 #ifdef CONFIG_IWLWIFI_DEBUG
        iwl_accumulative_statistics(priv, (__le32 *)&pkt->u.stats);
 #endif
+       actual_ack_cnt_delta = le32_to_cpu(pkt->u.stats.tx.actual_ack_cnt) -
+               le32_to_cpu(priv->statistics.tx.actual_ack_cnt);
+       expected_ack_cnt_delta = le32_to_cpu(
+                       pkt->u.stats.tx.expected_ack_cnt) -
+               le32_to_cpu(priv->statistics.tx.expected_ack_cnt);
+       ba_timeout_delta = le32_to_cpu(
+                       pkt->u.stats.tx.agg.ba_timeout) -
+               le32_to_cpu(priv->statistics.tx.agg.ba_timeout);
+       if ((priv->agg_tids_count > 0) &&
+               (expected_ack_cnt_delta > 0) &&
+               (((actual_ack_cnt_delta * 100) / expected_ack_cnt_delta) <
+                       ACK_CNT_RATIO) &&
+               (ba_timeout_delta > BA_TIMEOUT_CNT)) {
+               IWL_DEBUG_RADIO(priv,
+                       "actual_ack_cnt delta = %d, expected_ack_cnt = %d\n",
+                       actual_ack_cnt_delta, expected_ack_cnt_delta);
+
+#ifdef CONFIG_IWLWIFI_DEBUG
+               IWL_DEBUG_RADIO(priv, "rx_detected_cnt delta = %d\n",
+                       priv->delta_statistics.tx.rx_detected_cnt);
+               IWL_DEBUG_RADIO(priv,
+                       "ack_or_ba_timeout_collision delta = %d\n",
+                       priv->delta_statistics.tx.ack_or_ba_timeout_collision);
+#endif
+               IWL_DEBUG_RADIO(priv, "agg ba_timeout delta = %d\n",
+                       ba_timeout_delta);
+               if ((actual_ack_cnt_delta == 0) &&
+                       (ba_timeout_delta >=
+                               BA_TIMEOUT_MAX)) {
+                       IWL_DEBUG_RADIO(priv,
+                               "call iwl_force_reset(IWL_FW_RESET)\n");
+                       iwl_force_reset(priv, IWL_FW_RESET);
+               } else {
+                       IWL_DEBUG_RADIO(priv,
+                               "call iwl_force_reset(IWL_RF_RESET)\n");
+                       iwl_force_reset(priv, IWL_RF_RESET);
+               }
+       }
        /*
         * check for plcp_err and trigger radio reset if it exceeds
         * the plcp error threshold plcp_delta.