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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Matthew Jacob <mj@feral.com>
References: <4C2B07F5.6030801@delphij.net> <4C2B4D35.8060903@feral.com>
Date: Wed, 30 Jun 2010 23:49:20 +0200
In-Reply-To: <4C2B4D35.8060903@feral.com> (Matthew Jacob's message of "Wed, 30
	Jun 2010 06:57:09 -0700")
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Cc: freebsd-hackers@freebsd.org
Subject: Re: Supermicro BIOS's watchdog feature?
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Matthew Jacob <mj@feral.com> writes:
> Xin LI <delphij@delphij.net> writes:
> > It seems that ICH10R's watchdog is supported by ichwd(4) but
> > Supermicro BIOS needs some special treatments which is beyond what
> > ichwd(4) and watchdogd(8) would do...
> What do mean "special" treatment?

The watchdog timer can be disabled in hardware (by pulling the speaker
pin high during boot, IIRC).  Even if it is enabled, it can be caught
and ignored by the SMM firmware.  Some BIOSes have options to enable or
disable the watchdog timer, which I assume means that they flip a bit
that tells the firmware to either catch it or pass it through.

Unfortunately, although it is possible for the ichwd driver to detect
programatically (by checking an MSR) if the watchdog timer is disabled
in hardware, it is not possible to determine whether it is disabled in
firmware.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no