Re: can't switch CPU frequency while running on batterypower

[Ducrot Bruno <ducrot-kk6yZipjEM5g9hUCZPvPmw@public.gmane.org>]

On Tue, Jan 06, 2004 at 01:39:44PM -0800, Nate Lawson wrote:
> On Tue, 6 Jan 2004, Defiant wrote:
> > Nate Lawson wrote:
> > > This is most likely a problem with re-evaluation of _PSS after it has been
> > > changed.  I don't remember if Linux uses the notify on the processor
> > > object to re-evaluate _PSS.  If Linux does this correctly, it may be that
> > > the underlying firmware has a bug and you should use a more specific
> > > cpufreq driver (i.e. SpeedStep or whatever).  Some systems have a problem
> > > where they don't properly export firmware information to the ACPI
> > > performance states interface.
> >
> > uhm, I don't know why, but it is working now, using
> > CONFIG_X86_P4_CLOCKMOD instead of CONFIG_X86_SPEEDSTEP_ICH, even it is a
> > Pentium 4m, not Pentium 4.
> 
> Sure.  In general, it's better to use a hw-specific cpufreq driver instead
> of the generic ACPI one, even if the latter seems to work.  Many chipsets
> don't export the hw-specific information to ACPI correctly and thus ACPI
> performance states cpufreq should be a last resort.  If they still don't
> work, you should try multiple hw-specific drivers, as you did.
> 

What is strange though is that speedstep-ich is a non-acpi driver.

-- 
Ducrot Bruno

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


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