[syslinux] [RESEND][RFC GIT PATCHES] acpioff: COM32 module to shut off machine using ACPI

[Andy Walls]

On Sat, 2012-03-17 at 16:57 -0700, H. Peter Anvin wrote:
> On 03/17/2012 06:46 AM, Andy Walls wrote:
> > 
> > What I implemented with acpioff is not worth converting to a shared
> > component, in my opinion.  It is minimally functional and cannot be use
> > for general power management with ACPI.
> > 
> 
> A much bigger issue: we can't go into ACPI system mode; that is the
> prerogative of the OS.

Oh, but I do, in acpioff.c:

	acpi_initialize_subsystem();
	acpi_initialize_tables(NULL, 16, FALSE);
	acpi_load_tables();
	acpi_enable_subsystem(ACPI_FULL_INITIALIZATION);   <-- puts hardware in ACPI mode
	acpi_initialize_objects(ACPI_FULL_INITIALIZATION);
	acpi_enter_sleep_state_prep(ACPI_STATE_S5)
	acpi_enter_sleep_state(ACPI_STATE_S5);  <-- leave ACPI mode by virtue of power off
	acpi_terminate();    <-- leave ACPI mode if we couldn't power off


When pxelinux.0 or syslinux and a COM32 module are running, they are
filling the role of the OS, as far as the ACPICA is concerned.  (One
could be stricter and not allow COM32 modules to play part of that
role.)

Before control is transfered to a new OS with ACPI support, SYSLINUX, or
PXELINUX, and the COM32 module would need to ensure the hardware is not
in ACPI mode, by calling acpi_terminate().

Regards,
Andy

> 	-hpa