Re: _PDC method in DSDT

Ducrot Bruno
2003-06-23T10:07:44Z

On Sun, Jun 22, 2003 at 05:45:31PM -0700, David Moore wrote:
> Hi,
>
> Does anyone know the purpose or specification of the _PDC method of the
> DSDT? It's a reserved method that exists on my laptop (a Dell Latitude
> D600) but does not seem to be documented in the ACPI specification on
> the web.
>
> The reason I ask is that I'm interested in porting the cpufreq driver
> for Enhanced Speedstep to ACPI. Right now, the cpufreq driver has the
> tables of proper MSR register values encoded into the source, but a more
> elegant solution would be to get this information from ACPI. In my DSDT
> source I notice that when the _PDC method is called properly, the _PCT
> method will return FixedHardware addresses for the Enhanced Speedstep
> MSRs instead of its normal SystemIO ports. To get this to work on more
> than just my system, I should probably use the proper specification for
> calling _PDC rather than just making it work.
>
> Anyone have any suggestions?
>

Too late... A CPUFreq driver is already writen and is in the CPUFreq cvs.

--
Ducrot Bruno

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