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Subject: Re: [Qemu-devel] Hardware watchdogs (patch for discussion only)
From: Steve Fosdick <lists@pelvoux.nildram.co.uk>
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Date: Fri, 27 Feb 2009 09:55:31 +0000
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On Thu, 2009-02-26 at 14:45 +0000, Richard W.M. Jones wrote:

> The Intel 6300ESB in fact offers this possibility already.  As with
> other high-end watchdog hardware, it can be configured to send a
> "pretimer interrupt".  For example, if the watchdog is set to expire
> after 60 seconds, you can get an interrupt N seconds before this,
> which you can use to try a graceful shutdown.
> 
> Having said that, Linux watchdog software doesn't support this feature ...

Am I right in thinking that the kernel will not respond to an ACPI event
that indicates a power button has been pressed but forward it to
userspace where something (acpid) should respond?

If so there isn't much point in making the pre-timer interrupt do that
as we are assuming userspace is dead.  Perhaps instead it could use the
Alt-SysRq mechanism to do an emergency sync,reboot?

Regards,
Steve.