[SeaBIOS] [PATCH] apm: fix shutdown

[Kevin O'Connor]

On Thu, Jul 25, 2013 at 10:05:21AM +0200, Gerd Hoffmann wrote:
> Qemu commit 9ee59f3 removed the bochs bios apm interface emulation at
> port 0x8900.  That broke poweroff via APM.  Fix it by powering off the
> machine using the acpi pm control register.
> 
> Old code is left in, so seabios wil try both poweroff methods.  Cleaning
> that eventually up is left for another patch, after checking it isn't
> needed.  Qemu never implemented "Standby" and "Suspend", only
> "Shutdown", so it looks like there might be non-qemu use cases (bochs
> probably).
> 
> Easiest way to test this is the syslinux poweroff module; modern linux
> distros usually have CONFIG_APM turned off.

I agree that implementing APM using ACPI makes sense.  However, this
code is used by coreboot and CSM as well, so we can't hardcode the
ACPI address.  Ideally the code would scan the ACPI tables for
poweroff capability and store that so APM could use it later.

If QEMU never implemented standby/suspend, then I'm fine with dropping
that code.  (I agree putting that in a separate patch makes sense.)

-Kevin