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Commit 1db5950f authored by Trieu 'Andrew' Nguyen's avatar Trieu 'Andrew' Nguyen Committed by Reinette Chatre
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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: default avatarTrieu 'Andrew' Nguyen <trieux.t.nguyen@intel.com>
Signed-off-by: default avatarReinette Chatre <reinette.chatre@intel.com>
parent a9e10fb9

drivers/net/wireless/iwlwifi/iwl-agn.c

+13 −1
Original line number Diff line number Diff line
@@ -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)

drivers/net/wireless/iwlwifi/iwl-dev.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

drivers/net/wireless/iwlwifi/iwl-rx.c

+46 −0
Original line number Diff line number Diff line
@@ -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.