carl9170: fix spurious restart due to high latency

RX Stress tests of unidirectional bulk traffic with
bitrates of up to 220Mbit/s have revealed that the
fatal-event recovery logic [which was solely triggered
by an out-of-rx-buffer situation] is too aggressive.

The new method now "pings" the device and then
decides - based on the response - whenever
a restart is needed or not.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index d521bc2..4ae6a58 100644
--- a/drivers/net/wireless/ath/carl9170/main.c
+++ b/drivers/net/wireless/ath/carl9170/main.c
@@ -428,6 +428,7 @@ static void carl9170_cancel_worker(struct ar9170 *ar)
 	cancel_delayed_work_sync(&ar->led_work);
 #endif /* CONFIG_CARL9170_LEDS */
 	cancel_work_sync(&ar->ps_work);
+	cancel_work_sync(&ar->ping_work);
 	cancel_work_sync(&ar->ampdu_work);
 }
 
@@ -533,6 +534,21 @@ void carl9170_restart(struct ar9170 *ar, const enum carl9170_restart_reasons r)
 	 */
 }
 
+static void carl9170_ping_work(struct work_struct *work)
+{
+	struct ar9170 *ar = container_of(work, struct ar9170, ping_work);
+	int err;
+
+	if (!IS_STARTED(ar))
+		return;
+
+	mutex_lock(&ar->mutex);
+	err = carl9170_echo_test(ar, 0xdeadbeef);
+	if (err)
+		carl9170_restart(ar, CARL9170_RR_UNRESPONSIVE_DEVICE);
+	mutex_unlock(&ar->mutex);
+}
+
 static int carl9170_init_interface(struct ar9170 *ar,
 				   struct ieee80211_vif *vif)
 {
@@ -1614,6 +1630,7 @@ void *carl9170_alloc(size_t priv_size)
 		skb_queue_head_init(&ar->tx_pending[i]);
 	}
 	INIT_WORK(&ar->ps_work, carl9170_ps_work);
+	INIT_WORK(&ar->ping_work, carl9170_ping_work);
 	INIT_WORK(&ar->restart_work, carl9170_restart_work);
 	INIT_WORK(&ar->ampdu_work, carl9170_ampdu_work);
 	INIT_DELAYED_WORK(&ar->tx_janitor, carl9170_tx_janitor);