The queue stopping/waking functionality was broken in a way that could
cause the TX to stall if the right circumstances are met.
The problem was caused by tx_work, which is scheduled on each TX operation.
If the firmware buffer is full, tx_work does nothing. In combinition with
stopped queues or non-continues transfers, tx_work is never scheduled again.
Moreover the low watermark introduced by
9df86e2e702c6d5547aced7f241addd2d698bb11 never takes effect because of some
old code.
Solve this by scheduling tx_work every time tx_queue is non-empty and
firmware buffer is freed on tx_complete.
This also solves a possible but unlikely case: If less frames than the high
watermark are queued, but more than firmware buffer can hold. This results
in queues staying awake but the only scheduled tx_work doesn't transfer all
frames, so the remaining frames are stuck in the queue until more frames
get queued and tx_work is scheduled again.
Signed-off-by: David Gnedt <david.gnedt@xxxxxxxxxxx>
---
Sorry for the partly broken patches, I thought I configured my client the
right way. I tried to stop the mails at my mailserver, but it was mostly
already too late.
---
drivers/net/wireless/wl1251/tx.c | 48 +++++++++----------------------------
1 files changed, 12 insertions(+), 36 deletions(-)
diff --git a/drivers/net/wireless/wl1251/tx.c b/drivers/net/wireless/wl1251/tx.c
index 554b4f9..10112de 100644
--- a/drivers/net/wireless/wl1251/tx.c
+++ b/drivers/net/wireless/wl1251/tx.c
@@ -368,7 +368,7 @@ static void wl1251_tx_packet_cb(struct wl1251 *wl,
{
struct ieee80211_tx_info *info;
struct sk_buff *skb;
- int hdrlen, ret;
+ int hdrlen;
u8 *frame;
skb = wl->tx_frames[result->id];
@@ -407,40 +407,12 @@ static void wl1251_tx_packet_cb(struct wl1251 *wl,
ieee80211_tx_status(wl->hw, skb);
wl->tx_frames[result->id] = NULL;
-
- if (wl->tx_queue_stopped) {
- wl1251_debug(DEBUG_TX, "cb: queue was stopped");
-
- skb = skb_dequeue(&wl->tx_queue);
-
- /* The skb can be NULL because tx_work might have been
- scheduled before the queue was stopped making the
- queue empty */
-
- if (skb) {
- ret = wl1251_tx_frame(wl, skb);
- if (ret == -EBUSY) {
- /* firmware buffer is still full */
- wl1251_debug(DEBUG_TX, "cb: fw buffer "
- "still full");
- skb_queue_head(&wl->tx_queue, skb);
- return;
- } else if (ret < 0) {
- dev_kfree_skb(skb);
- return;
- }
- }
-
- wl1251_debug(DEBUG_TX, "cb: waking queues");
- ieee80211_wake_queues(wl->hw);
- wl->tx_queue_stopped = false;
- }
}
/* Called upon reception of a TX complete interrupt */
void wl1251_tx_complete(struct wl1251 *wl)
{
- int i, result_index, num_complete = 0;
+ int i, result_index, num_complete = 0, queue_len;
struct tx_result result[FW_TX_CMPLT_BLOCK_SIZE], *result_ptr;
unsigned long flags;
@@ -471,18 +443,22 @@ void wl1251_tx_complete(struct wl1251 *wl)
}
}
- if (wl->tx_queue_stopped
- &&
- skb_queue_len(&wl->tx_queue) <= WL1251_TX_QUEUE_LOW_WATERMARK){
+ queue_len = skb_queue_len(&wl->tx_queue);
- /* firmware buffer has space, restart queues */
+ if ((num_complete > 0) && (queue_len > 0)) {
+ /* firmware buffer has space, reschedule tx_work */
+ wl1251_debug(DEBUG_TX, "tx_complete: reschedule tx_work");
+ ieee80211_queue_work(wl->hw, &wl->tx_work);
+ }
+
+ if (wl->tx_queue_stopped &&
+ queue_len <= WL1251_TX_QUEUE_LOW_WATERMARK) {
+ /* tx_queue has space, restart queues */
wl1251_debug(DEBUG_TX, "tx_complete: waking queues");
spin_lock_irqsave(&wl->wl_lock, flags);
ieee80211_wake_queues(wl->hw);
wl->tx_queue_stopped = false;
spin_unlock_irqrestore(&wl->wl_lock, flags);
- ieee80211_queue_work(wl->hw, &wl->tx_work);
-
}
/* Every completed frame needs to be acknowledged */
--
1.7.0.4
--
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