| From stable-bounces@linux.kernel.org Fri Oct 27 10:09:29 2006 |
| Message-ID: <454230E7.3090909@lwfinger.net> |
| Date: Fri, 27 Oct 2006 11:16:39 -0500 |
| From: Michael Buesch <mb@bu3sch.de> |
| MIME-Version: 1.0 |
| To: stable@kernel.org |
| Cc: Michael Buesch <mb@bu3sch.de> |
| Subject: bcm43xx: fix watchdog timeouts. |
| Content-Type: text/plain; charset="us-ascii" |
| |
| From: Michael Buesch <mb@bu3sch.de> |
| |
| This fixes a netdev watchdog timeout problem. |
| The problem is caused by a needed netif_tx_disable |
| in the hardware calibration code and can be shown by the |
| following timegraph. |
| |
| |---5secs - ~10 jiffies time---|---|OOPS |
| ^ ^ |
| last real TX periodic work stops netif |
| |
| At OOPS, the following happens: |
| The watchdog timer triggers, because the timeout of 5secs |
| is over. The watchdog first checks for stopped TX. |
| _Usually_ TX is only stopped from the TX handler to indicate |
| a full TX queue. But this is different. We need to stop TX here, |
| regardless of the TX queue state. So the watchdog recognizes |
| the stopped device and assumes it is stopped due to full |
| TX queues (Which is a _wrong_ assumption in this case). It then |
| tests how far the last TX has been in the past. If it's more than |
| 5secs (which is the case for low or no traffic), it will fire |
| a TX timeout. |
| |
| Acked-by: John W. Linville <linville@tuxdriver.com> |
| Signed-off-by: Michael Buesch <mb@bu3sch.de> |
| Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| Signed-off-by: Chris Wright <chrisw@sous-sol.org> |
| |
| --- |
| drivers/net/wireless/bcm43xx/bcm43xx_main.c | 8 ++++++++ |
| 1 file changed, 8 insertions(+) |
| |
| --- linux-2.6.18.1.orig/drivers/net/wireless/bcm43xx/bcm43xx_main.c |
| +++ linux-2.6.18.1/drivers/net/wireless/bcm43xx/bcm43xx_main.c |
| @@ -3165,7 +3165,15 @@ static void bcm43xx_periodic_work_handle |
| |
| badness = estimate_periodic_work_badness(bcm->periodic_state); |
| mutex_lock(&bcm->mutex); |
| + |
| + /* We must fake a started transmission here, as we are going to |
| + * disable TX. If we wouldn't fake a TX, it would be possible to |
| + * trigger the netdev watchdog, if the last real TX is already |
| + * some time on the past (slightly less than 5secs) |
| + */ |
| + bcm->net_dev->trans_start = jiffies; |
| netif_tx_disable(bcm->net_dev); |
| + |
| spin_lock_irqsave(&bcm->irq_lock, flags); |
| if (badness > BADNESS_LIMIT) { |
| /* Periodic work will take a long time, so we want it to |
