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From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH -rt DO NOT APPLY] Fix for tg3 networking lockup
Date: Tue, 08 Aug 2006 15:00:06 -0700 (PDT)
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From: Steven Rostedt <rostedt@goodmis.org>
Date: Tue, 8 Aug 2006 08:24:10 -0400 (EDT)

> Of the 4 timers, only one is a timeout. The other three expire every time,
> forcing the timer wheel into effect.  Even though it's one timer
> implementing 4, it's expensive to use it as a watchdog.

It's not a watchdog, the timer continually fires.

It is the on-chip ASF firmware that "times out" if it does not
see  the heartbeat message from the driver within 5 seconds.

The driver timer in question runs every 2 seconds to write this
heartbeat message to the chip.