From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [patch]Add a new reboot method
Date: Thu, 29 May 2008 15:59:26 +0100
Message-ID: <20080529155926.17dffcf6@core>
References: <483EC73C.76E4.0078.0@novell.com>
	<C4646E6C.2165E%keir.fraser@eu.citrix.com>
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To: Keir Fraser <keir.fraser@eu.citrix.com>
Cc: Huacai Chen <huacai.chen@intel.com>, xen-devel@lists.xensource.com, Jan Beulich <jbeulich@novell.com>
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On Thu, 29 May 2008 14:30:04 +0100
Keir Fraser <keir.fraser@eu.citrix.com> wrote:

> On 29/5/08 14:09, "Jan Beulich" <jbeulich@novell.com> wrote:
> 
> >> You might want to boot a 32bit kernel and try acpi=off, if that does the
> >> trick then its (another) ACPI bug and the cf9 is red herring ?
> > 
> > As Keir also pointed out, there's no ACPI involved in rebooting. I also
> > did verify (in a 32-bit kernel) that it's the keyboard boot sequence that
> > causes the machine to hang.
> 
> ACPI *can* be involved in rebooting though, via FADT's RESET_REGISTER.
> Question is: why does Linux ignore this reboot method? 

It doesn't. Well at the least upstream version doesn't. We default to
keyboard currently but that probably wants reconsidering for modern
systems.

Alan