Re: ACPI _SUN

[Len Brown <lenb@kernel.org>]

On Friday 19 January 2007 11:37, Bruno Ducrot wrote:
> On Fri, Jan 19, 2007 at 03:26:26PM +0530, Mohan Kumar Jami wrote:
> > Hi,
> > 
> > I have couple of questions related to _SUN object.
> > 
> > 1) Is _SUN object be present DSDT tables?
> 
> They are defined under DSDT or RSDT tables as any other ACPI objects
> populating the ACPI namespace.

The DSDT and all the SSDT's listed in the RSDT are all loaded at boot-time.

However, the BIOS AML can also explicitly Load additional "dynamic" SSDTs
at run-time -- and can also Unload an SSDT.
In this way, objects in the name space can appear and go away at run-time.

_SUN, Slot User Number, is an (optional) property of an object.
So for it to change at run-time, the object that contains it
would have to go away and then come back.

cheers,
-Len

> > 2) How this DSDT table get updated?
> 
> They can't be updated.
> 
> > 3) Is DSDT table is static binary file or it can be dynamically updated?
> 
> A DSDT table is not a static binary file.  On most i386 or amd64
> architectures, DSDT and SSDT are part of the BIOS.
> The BIOS uncompressed and copyied them into main memory at the
> POST stage since the ROM is too limited in size.
> 
> > 4) Who will update the DSDT tables?
> 
> By the customer via BIOS updates obtained from the vendor.
> 
> Cheers,
>