Re: [PATCH] x86: default to reboot via ACPI

Maciej W. Rozycki
2008-08-26T13:25:54Z

On Tue, 26 Aug 2008, Avi Kivity wrote:

> Most machines are recent machines.

This is a bold statement I would say. Any numbers to back it up?

> If a machine doesn't have acpi, this change is safe.
>
> If a machine has acpi, but doesn't have the reset register set in the
> FADT, this change is safe.
>
> If a machine has acpi, and the reset register is set incorrectly, this
> change is safe.
>
> If a machine has acpi, and the reset register is wired to the launch
> controller, then perhaps this change is unsafe. Don't issue sysrq-b on
> such machines.

If a machine has ACPI and it is broken randomly, then the results can be
arbitrary. Hopefully not destructively. If even such a simple thing as
wiring the reset line so that it functions correctly can be got wrong,
more so can be more complex matters.

Failing a better alternative, I suppose the change has to go in though.

Maciej