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Commit 06f7bc7d authored by Juuso Oikarinen's avatar Juuso Oikarinen Committed by John W. Linville
Browse files

wl1271: Fix queue stopping/waking for TX path 



The queue stopping/waking functionality was broken in a way that could
cause huge latencies in TX transfers and even cause the TX to stall in the
right circumstances. Correct these problems.

Signed-off-by: default avatarJuuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: default avatarKalle Valo <kalle.valo@nokia.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 15305498

drivers/net/wireless/wl12xx/wl1271.h

+2 −1
Original line number Original line Diff line number Diff line
@@ -491,7 +491,8 @@ int wl1271_plt_stop(struct wl1271 *wl); 




#define WL1271_DEFAULT_POWER_LEVEL 0

#define WL1271_DEFAULT_POWER_LEVEL 0





#define WL1271_TX_QUEUE_MAX_LENGTH 20

#define WL1271_TX_QUEUE_LOW_WATERMARK  10

#define WL1271_TX_QUEUE_HIGH_WATERMARK 25





/* WL1271 needs a 200ms sleep after power on, and a 20ms sleep before power

/* WL1271 needs a 200ms sleep after power on, and a 20ms sleep before power

   on in case is has been shut down shortly before */

   on in case is has been shut down shortly before */

drivers/net/wireless/wl12xx/wl1271_main.c

+5 −7
Original line number Original line Diff line number Diff line
@@ -791,15 +791,13 @@ static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb) 
	 * The workqueue is slow to process the tx_queue and we need stop

	 * The workqueue is slow to process the tx_queue and we need stop

	 * the queue here, otherwise the queue will get too long.

	 * the queue here, otherwise the queue will get too long.

	 */

	 */

	if (skb_queue_len(&wl->tx_queue) >= WL1271_TX_QUEUE_MAX_LENGTH) {

	if (skb_queue_len(&wl->tx_queue) >= WL1271_TX_QUEUE_HIGH_WATERMARK) {

		ieee80211_stop_queues(wl->hw);

		wl1271_debug(DEBUG_TX, "op_tx: stopping queues");





		/*

		spin_lock_irqsave(&wl->wl_lock, flags);

		 * FIXME: this is racy, the variable is not properly

		ieee80211_stop_queues(wl->hw);

		 * protected. Maybe fix this by removing the stupid

		 * variable altogether and checking the real queue state?

		 */

		set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);

		set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);

		spin_unlock_irqrestore(&wl->wl_lock, flags);

	}

	}





	return NETDEV_TX_OK;

	return NETDEV_TX_OK;

drivers/net/wireless/wl12xx/wl1271_tx.c

+15 −13
Original line number Original line Diff line number Diff line
@@ -278,22 +278,12 @@ void wl1271_tx_work(struct work_struct *work) 




		ret = wl1271_tx_frame(wl, skb);

		ret = wl1271_tx_frame(wl, skb);

		if (ret == -EBUSY) {

		if (ret == -EBUSY) {

			/* firmware buffer is full, stop queues */

			/* firmware buffer is full, lets stop transmitting. */

			wl1271_debug(DEBUG_TX, "tx_work: fw buffer full, "

				     "stop queues");

			ieee80211_stop_queues(wl->hw);

			set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);

			skb_queue_head(&wl->tx_queue, skb);

			skb_queue_head(&wl->tx_queue, skb);

			goto out_ack;

			goto out_ack;

		} else if (ret < 0) {

		} else if (ret < 0) {

			dev_kfree_skb(skb);

			dev_kfree_skb(skb);

			goto out_ack;

			goto out_ack;

		} else if (test_and_clear_bit(WL1271_FLAG_TX_QUEUE_STOPPED,

					      &wl->flags)) {

			/* firmware buffer has space, restart queues */

			wl1271_debug(DEBUG_TX,

				     "complete_packet: waking queues");

			ieee80211_wake_queues(wl->hw);

		}

		}

	}

	}
@@ -380,8 +370,6 @@ void wl1271_tx_complete(struct wl1271 *wl) 
	u32 count, fw_counter;

	u32 count, fw_counter;

	u32 i;

	u32 i;





	wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);



	/* read the tx results from the chipset */

	/* read the tx results from the chipset */

	wl1271_read(wl, le32_to_cpu(memmap->tx_result),

	wl1271_read(wl, le32_to_cpu(memmap->tx_result),

		    wl->tx_res_if, sizeof(*wl->tx_res_if), false);

		    wl->tx_res_if, sizeof(*wl->tx_res_if), false);
@@ -393,6 +381,7 @@ void wl1271_tx_complete(struct wl1271 *wl) 
				tx_result_host_counter), fw_counter);

				tx_result_host_counter), fw_counter);





	count = fw_counter - wl->tx_results_count;

	count = fw_counter - wl->tx_results_count;

	wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);





	/* verify that the result buffer is not getting overrun */

	/* verify that the result buffer is not getting overrun */

	if (unlikely(count > TX_HW_RESULT_QUEUE_LEN))

	if (unlikely(count > TX_HW_RESULT_QUEUE_LEN))
@@ -409,6 +398,19 @@ void wl1271_tx_complete(struct wl1271 *wl) 




		wl->tx_results_count++;

		wl->tx_results_count++;

	}

	}



	if (test_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags) &&

	    skb_queue_len(&wl->tx_queue) <= WL1271_TX_QUEUE_LOW_WATERMARK) {

		unsigned long flags;



		/* firmware buffer has space, restart queues */

		wl1271_debug(DEBUG_TX, "tx_complete: waking queues");

		spin_lock_irqsave(&wl->wl_lock, flags);

		ieee80211_wake_queues(wl->hw);

		clear_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);

		spin_unlock_irqrestore(&wl->wl_lock, flags);

		ieee80211_queue_work(wl->hw, &wl->tx_work);

	}

}

}





/* caller must hold wl->mutex */

/* caller must hold wl->mutex */