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;
