Re: [ACPI] _PDC method in DSDT

Ducrot Bruno
2003-06-26T10:40:41Z

On Tue, Jun 24, 2003 at 02:47:52PM -0700, David Moore wrote:
> On Tue, 2003-06-24 at 02:18, Ducrot Bruno wrote:
> > Then only concern I may have for is still the _PDC method. It is currently
> > only documented in a MS document. It is defined as an optional method
> > used by the OS in order to be somehow compatible with older releases
> > of Windows. But it has the folowing:
> >
> > Arguments:
> > Arg0 (buffer):
> > DWORD 0: Revision Id
> > DWORD 1: Number of capabilities DWORDs in buffer
> > DWORD 2-n: Capabilities DWORDs, where each bit
> > defines capabilities and features supported by the OSPM for
> > processor power management.
> > The definitions and meaning of each capabilities bit is vendor
> > specific, and shared with OSPM by the vendor.
> >
> > Result Code:
> > None
> >
> > Then give us now the correct values to be passed for Pentium-M found
> > in Centrino platform, and I will be glad to do the break of cpufreq/acpi.c
> > for you.
> >
>
> Dword 0 should be 0x1
> Dword 1 should be 0x1
> Dword 2 should be 0x1
>
> The 0x1 in Dword 2 indicates that the driver supports Enhanced
> Speedstep. In my DSDT, Dwords 0 and 1 are ignored anyway, but the
> values above should be correct.

Sound like ok, but not for Dword 0. Will look more at it then.

>
> Feel free to do the split into two files if you think that's the way to
> go. I'm going to submit my patch to the cpufreq list anyway under a
> separate email, just so it exists for the record. You might change your
> mind after seeing it. I also have a patch that fixes a few bugs in the
> current cpufreq/acpi.c.

Yes, I saw some of those bugs too. Will look at it a little bit more.

Note that I am not really against at, but I prefer to see at first all
implications of supporting this method.

--
Ducrot Bruno

-- Which is worse: ignorance or apathy?
-- Don't know. Don't care.