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

[Andy Walls]

Hi Erwan,

On Fri, 2012-03-16 at 08:11 +0100, Erwan Velu wrote:
> Le 03/03/2012 14:46, Andy Walls a écrit :
> 
> Does this work can be somehow merged or integrated with the acpi stuff I 
> did in gpllib ?
> The need of acpi is somehow global to syslinux, duplicating the efforts 
> in every com32 module sounds like duplicating the efforts and preventing 
> have a global interface.
> 
> Having something usable for all com32 modules would be nicer.

I completely agree we need something shared for all com32 modules.

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 fully functional COM32 ACPICA instance can be created and shared, but
a few things are needed from the SYSLINUX core:

1. Threads.  (The LwIP branch has thread support.)

2. Mutexes and Semaphores. (I assume the LwIP branch has these too, no?)

3. IRQ line allocation and management, including hooking up a custom
interrupt handler and handling of interrupt acknowledgements with the
hardware.

4. A decision on how COM32 modules should interact with the ACPICA: as a
component of the "OS" or as a "userspace" program.



Before I implemented acpioff, I looked at your ACPI code in gplinclude
and gpllib.  I assessed that it was a good, lightweight ACPI table
parser, but that it couldn't call any ACPI methods.

The ACPICA also has its own parser.  If you wanted to integrate an
ACPICA instance with the existing gpllib ACPI code, one way would be to
convert the existing gpllib routines to call into an ACPICA instance's
parser to do the parsing.

> Erwan,


Regards,
Andy