On Mon, Dec 11, 2017 at 09:51:29PM +0100, Enrico Mioso wrote: > Hello guys, and sorry for the big CC list. > I would like to point out about a bug who survived for years - at least from 2015 until now, regarding the Ralink driver getting stuck, and in some cases not being able to recover. > The problem manifested with an MT7620A chip, and the wireless card inside the WL-330N3G device. > The error message is in rt2x00/rt2x00queue.c . > > This bug was discussed, and a patch proposed, in this thread: > https://lists.openwrt.org/pipermail/openwrt-devel/2015-September/thread.html#35778 > > I would like to help if possible - I have the have both an Archer MR200, and the WL330n3G hardware. > BTW, the Archer MR200 is a nice MT7610 device, and the problem manifests itself, see: > https://forum.openwrt.org/viewtopic.php?id=64293&p=6 > > Any help, hint, anything would be apreciated. > thank you to all. First I would try to remove this patch: http://git.lede-project.org/?p=source.git;a=blob;f=package/kernel/mac80211/patches/600-23-rt2x00-rt2800mmio-add-a-workaround-for-spurious-TX_F.patch and see if it makes things better. However I think for the stuck problem we need tx status timeout mechanism similar like for rt2800usb. Attached patch can mitigate "Dropping frame due to full tx queue" errors. I did not test it, so it can be totally broken. Regards Stanislaw
diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c index ecc96312a370..c8a6f163102f 100644 --- a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c @@ -152,16 +152,6 @@ void rt2x00mac_tx(struct ieee80211_hw *hw, if (unlikely(rt2x00queue_write_tx_frame(queue, skb, control->sta, false))) goto exit_fail; - /* - * Pausing queue has to be serialized with rt2x00lib_txdone(). Note - * we should not use spin_lock_bh variant as bottom halve was already - * disabled before ieee80211_xmit() call. - */ - spin_lock(&queue->tx_lock); - if (rt2x00queue_threshold(queue)) - rt2x00queue_pause_queue(queue); - spin_unlock(&queue->tx_lock); - return; exit_fail: diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c b/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c index a2c1ca5c76d1..39d523bbb661 100644 --- a/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00queue.c @@ -714,6 +714,13 @@ int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb, rt2x00queue_write_tx_descriptor(entry, &txdesc); rt2x00queue_kick_tx_queue(queue, &txdesc); + /* + * Pausing queue has to be serialized with rt2x00lib_txdone(), so we + * do this under queue->tx_lock. Bottom halve was already disabled + * before ieee80211_xmit() call. + */ + if (rt2x00queue_threshold(queue)) + rt2x00queue_pause_queue(queue); out: spin_unlock(&queue->tx_lock); return ret;
