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>

3 files changed, 20 insertions, 2 deletions

diff --git a/drivers/net/wireless/ath/carl9170/carl9170.h b/drivers/net/wireless/ath/carl9170/carl9170.h
index b69d31972c77..d07ff7f2fd92 100644
--- a/drivers/net/wireless/ath/carl9170/carl9170.h
+++ b/drivers/net/wireless/ath/carl9170/carl9170.h
@@ -215,7 +215,7 @@ enum carl9170_restart_reasons {
         CARL9170_RR_TOO_MANY_FIRMWARE_ERRORS,
         CARL9170_RR_WATCHDOG,
         CARL9170_RR_STUCK_TX,
-        CARL9170_RR_SLOW_SYSTEM,
+        CARL9170_RR_UNRESPONSIVE_DEVICE,
         CARL9170_RR_COMMAND_TIMEOUT,
         CARL9170_RR_TOO_MANY_PHY_ERRORS,
         CARL9170_RR_LOST_RSP,
@@ -287,6 +287,7 @@ struct ar9170 {
 
         /* reset / stuck frames/queue detection */
         struct work_struct restart_work;
+        struct work_struct ping_work;
         unsigned int restart_counter;
         unsigned long queue_stop_timeout[__AR9170_NUM_TXQ];
         unsigned long max_queue_stop_timeout[__AR9170_NUM_TXQ];
diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index d521bc2b0496..4ae6a5849076 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);
diff --git a/drivers/net/wireless/ath/carl9170/usb.c b/drivers/net/wireless/ath/carl9170/usb.c
index d8607f4c144d..ddf5373ee689 100644
--- a/drivers/net/wireless/ath/carl9170/usb.c
+++ b/drivers/net/wireless/ath/carl9170/usb.c
@@ -431,7 +431,7 @@ static void carl9170_usb_rx_complete(struct urb *urb)
                          * device.
                          */
 
-                        carl9170_restart(ar, CARL9170_RR_SLOW_SYSTEM);
+                        ieee80211_queue_work(ar->hw, &ar->ping_work);
                 }
         } else {
                 /*