Re: [PATCH] ACPI: Add reboot mechanism

From: Aaron Durbin
Date: Tue Jul 17 2007 - 11:08:43 EST


On 7/17/07, Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:
On 7/17/07, Andi Kleen <ak@xxxxxxx> wrote:
> On Monday 16 July 2007 20:00:19 Aaron Durbin wrote:
> >
> > Add the ability to reset the machine using the RESET_REG in ACPI's FADT table.
>
> Why? I had such a patch at some point as experiment, but it never
> helped actually fix a box.
>
system without superio, should still have SMI to simulate one keyboard
controller. So the key board reset still works.

This is true if SMIs are still flowing, and the SMI handler correctly handles
the reset properly. I have seen cases where the SMI handler is broken which
causes the system to perpetually hang. Utilizing the exposed reset mechanism
in ACPI should reset the system every time. However, if the reset fails it
will fall back to the keyboard controller.

-Aaron
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