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From: David Miller <davem@davemloft.net>
To: komurojun-mbn@nifty.com
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PLEASE REVERT] "Add a WARN_ON_ONCE" at net/sched/sch_generic.c:
Date: Tue, 27 May 2008 06:14:42 -0700 (PDT)	[thread overview]
Message-ID: <20080527.061442.193726441.davem@davemloft.net> (raw)
In-Reply-To: <20080527213424.125e15dc.komurojun-mbn@nifty.com>

From: Komuro <komurojun-mbn@nifty.com>
Date: Tue, 27 May 2008 21:34:24 +0900

> I think the transmit timeout indicates 
> that the cable is not connected or the irq is conflict.

The MAC of the chip transmits and ACKs the packet in the hardware even
if the link is down.  The packet is simply dropped.

Also, when the link goes down, the driver should mark the device as
such.  In such a state, the generic networking does not pass new
packets to the driver.

Therefore, transmit timeouts in this case are a hardware
or driver error.

If there is an IRQ issue, that is an error that'd we would like to
have as much information as possible to diagnose.  So the warning is
still entirely appropriate.

I sense that you are seeing this warning triggered, and if so I
would suggest that you investigate it fully as it should not be
happening under normal circumstances.

  reply	other threads:[~2008-05-27 13:14 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-25  2:23 [PLEASE REVERT] "Add a WARN_ON_ONCE" at net/sched/sch_generic.c: Komuro
2008-05-25 12:10 ` David Miller
2008-05-27 12:34   ` Komuro
2008-05-27 13:14     ` David Miller [this message]
2008-07-29 12:53 ` NETDEV WATCHDOG: wifi0: transmit timed out Komuro
2008-07-29 13:43   ` Justin Mattock
2008-07-29 13:58   ` Arjan van de Ven
2008-07-29 20:47     ` David Miller
2008-07-29 22:48       ` Justin Mattock
2008-07-30 11:41         ` Dan Williams
2008-07-30 11:48   ` Komuro
2008-07-30 13:22     ` Arjan van de Ven
2008-07-30 14:55       ` Justin Mattock

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