Re: [Qemu-devel] [SeaBIOS] [edk2] (PAM stuff) reset doesn't work on OVMF + SeaBIOS CSM

[Kevin O'Connor]

On Mon, Feb 18, 2013 at 09:12:46PM +0000, David Woodhouse wrote:
> The i440fx data sheet (§3.0) appears to say that the default values are
> loaded on a *hard* reset, not a soft reset. And a reset invoked by the
> keyboard controller (as SeaBIOS does) is a *soft* reset. The only way to
> do a *hard* reset from software that's mentioned in the datasheet is the
> PMC turbo/reset control register (port 0x93). And that, presumably, is
> chipset-dependent and not something we can easily use from the reset
> vector without doing a bunch of hardware probing.

The ACPI v2 spec describes a "hard" reset register.  SeaBIOS could
extract it from the FADT and then use it.  Of course, we'd probably
want to update the QEMU ACPI tables to implement ACPI v2 then.

-Kevin