[rt2x00-users] rt2800usb stops at random

Stanislaw Gruszka sgruszka at redhat.com
Mon Jul 2 19:11:51 AEST 2012

On Wed, Jun 27, 2012 at 03:56:45PM -0300, Franco Miceli wrote:
> The patch worked like a charm. The problem did not occur again.
> One question though, what would be the effects of a *rx queue overwrite*? I
> mean from the users perspective.
Possible kernel crash.

I'm pasting different patch. I believe this one is the right fix for
the problem. Please test it (without previous patch) and let us know.


>From e899a84a6e9bec0ce653713a48ca121cd754430c Mon Sep 17 00:00:00 2001
From: Stanislaw Gruszka <sgruszka at redhat.com>
Date: Mon, 2 Jul 2012 09:42:14 +0200
Subject: [PATCH] rt2x00usb: fix indexes ordering on RX queue kick

On rt2x00_dmastart() we increase index specified by Q_INDEX and on
rt2x00_dmadone() we increase index specified by Q_INDEX_DONE. So entries
between Q_INDEX_DONE and Q_INDEX are those we currently process in the
hardware. Entries between Q_INDEX and Q_INDEX_DONE are those we can
submit to the hardware.

According to that fix rt2x00usb_kick_queue(), as we need to submit rx
entries that are not processed by the hardware. It worked before only
for empty queue, otherwise was broken.

Note that for TX queues indexes ordering are ok. We need to kick entries
that have filled skb, but was not submitted to the hardware, i.e.
strted from Q_INDEX_DONE and have ENTRY_DATA_PENDING bit set.

>From practical standpoint this patch fixes AP mode connection hangs.

Signed-off-by: Stanislaw Gruszka <sgruszka at redhat.com>
 drivers/net/wireless/rt2x00/rt2x00usb.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/wireless/rt2x00/rt2x00usb.c b/drivers/net/wireless/rt2x00/rt2x00usb.c
index d357d1e..74ecc33 100644
--- a/drivers/net/wireless/rt2x00/rt2x00usb.c
+++ b/drivers/net/wireless/rt2x00/rt2x00usb.c
@@ -436,8 +436,8 @@ void rt2x00usb_kick_queue(struct data_queue *queue)
 	case QID_RX:
 		if (!rt2x00queue_full(queue))
-						   Q_INDEX_DONE,
+						   Q_INDEX_DONE,

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