This patch is not upstream yet...

From 34c75818bfcd65e54fed9fe852fc41aba8cf233d Mon Sep 17 00:00:00 2001

From: Wey-Yi Guy <wey-yi.w.guy@intel.com>

Date: Thu, 4 Mar 2010 13:38:59 -0800

Subject: [PATCH 15/17] iwlwifi: Recover TX flow failure

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 BA_TIMEOUT_MAX, no tx packets can be delivered.

Reloading the uCode and bring the system back to normal operational

state.

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

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

diff -up linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-agn.c.orig linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-agn.c

--- linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-agn.c.orig	2010-03-22 15:48:54.000000000 -0400

+++ linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-agn.c	2010-03-22 16:06:01.000000000 -0400

@@ -2559,10 +2559,21 @@ static int iwl_mac_ampdu_action(struct i

 			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->_agn.agg_tids_count++;

+			IWL_DEBUG_HT(priv, "priv->_agn.agg_tids_count = %u\n",

+				     priv->_agn.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->_agn.agg_tids_count > 0)) {

+			priv->_agn.agg_tids_count--;

+			IWL_DEBUG_HT(priv, "priv->_agn.agg_tids_count = %u\n",

+				     priv->_agn.agg_tids_count);

+		}

 		if (test_bit(STATUS_EXIT_PENDING, &priv->status))

 			return 0;

 		else

diff -up linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-core.c.orig linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-core.c

--- linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-core.c.orig	2010-03-22 16:08:56.000000000 -0400

+++ linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-core.c	2010-03-22 16:08:53.000000000 -0400

@@ -1494,6 +1494,7 @@ int iwl_init_drv(struct iwl_priv *priv)

 	priv->band = IEEE80211_BAND_2GHZ;

 	priv->iw_mode = NL80211_IFTYPE_STATION;

+	priv->_agn.agg_tids_count = 0;

 	priv->current_ht_config.sm_ps = WLAN_HT_CAP_SM_PS_DISABLED;

diff -up linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-dev.h.orig linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-dev.h

--- linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-dev.h.orig	2010-03-22 15:48:54.000000000 -0400

+++ linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-dev.h	2010-03-22 16:06:01.000000000 -0400

@@ -1206,6 +1206,16 @@ struct iwl_priv {

 	u16 beacon_int;

 	struct ieee80211_vif *vif;

+	union {

+		struct {

+			/*

+			 * reporting the number of tids has AGG on. 0 means

+			 * no AGGREGATION

+			 */

+			u8 agg_tids_count;

+		} _agn;

+	};

+

 	/*Added for 3945 */

 	void *shared_virt;

 	dma_addr_t shared_phys;

diff -up linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-rx.c.orig linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-rx.c

--- linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-rx.c.orig	2010-03-22 16:02:35.000000000 -0400

+++ linux-2.6.32.noarch/drivers/net/wireless/iwlwifi/iwl-rx.c	2010-03-22 16:06:01.000000000 -0400

@@ -550,9 +550,18 @@ static void iwl_rx_calc_noise(struct iwl

 #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"

 /*

- * This function checks for plcp error.

+ * This function checks for plcp error, ACK count ratios, aggregated BA

+ * timeout retries.

+ * - When the ACK count ratio is 0 and aggregated BA timeout retries is

+ * exceeding the BA_TIMEOUT_MAX, it will recover the failure by resetting

+ * the firmware.

  * - When the plcp error is exceeding the thresholds, it will reset the radio

  * to improve the throughput.

  */

@@ -562,6 +571,36 @@ void iwl_recover_from_statistics(struct 

 	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;

+

+	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->_agn.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);

+		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);

+		}

+	}

 	/*

 	 * check for plcp_err and trigger radio reset if it exceeds