Re: IBM R40 FFixedHW register?

[Nate Lawson <nate-Y6VGUYTwhu0@public.gmane.org>]

On Wed, 22 Oct 2003, Ducrot Bruno wrote:
> On Tue, Oct 21, 2003 at 03:39:55PM -0700, Nate Lawson wrote:
> > I'm testing out my new cpu driver for FreeBSD and came across an
> > interesting case in supporting Px states.  They work great on several
> > laptops but the R40 can't set Px states.  I looked at the ASL and found
> > that the control/status register pair is FFixedHW.
> >
> >             Return (Package (0x02)
> >             {
> >                 ResourceTemplate ()
> >                 {
> >                     Register (FFixedHW, 0x40, 0x00, 0x0000000000000199)
> >                 },
> >
> >                 ResourceTemplate ()
> >                 {
> >                     Register (FFixedHW, 0x10, 0x00, 0x0000000000000198)
> >                 }
> >             }
> >
> > I guess I have to find the datasheet for that model to figure out how to
> > access those registers.  Anyone come across this before?  What space are
> > those actually in (IO, Memory, ??).  The register widths are also strange
> > (64 and 16 bits).
>
> They are MSRs for Pentium-M found in Centrino platforms, but acpi spec would
> only say you that you have to contact the CPU vendor.

Ah, thank you.  That makes sense.  How do you decide which platform you
are on to determine how to interpret FFixedHW resources?  Check the vendor
ID string for the ASL?  Check CPU or chipset type?  It could be that
FFixedHW is MSR on x86 but some other thing (EFI) on ia64.

For this particular laptop, should I be looking in the chipset guide or
the CPU guide?

-Nate


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