Re: ACPI throttling changes

On Thu, Dec 11, 2003 at 11:53:31AM -0800, Nate Lawson wrote:
> On Thu, 11 Dec 2003, Ducrot Bruno wrote:
> > On Wed, Dec 10, 2003 at 10:06:45AM -0800, Nate Lawson wrote:
> > > On Wed, 10 Dec 2003, Lukas Ertl wrote:
> > > > On Tue, 9 Dec 2003, Nate Lawson wrote:
> > > > > I'm working on a shared CPU frequency control driver.  One step is to
> > > > > remove some of the autonomy of the throttling portion of acpi_cpu.
> > > > > Please test this patch if you have a machine which supports throttling.
> > > >
> > > > Apropos CPU frequency: is there a way to find out at what frequency the
> > > > CPU is running?  And shouldn't SpeedStep have an influence on that?  (Or
> > > > is SpeedStep not supported?)
> > >
> > > This is getting a bit off-topic.  It's too early to discuss how all the
> > > different parts of cpufreq work.  The answer is "yes and no", depending on
> > > which underlying technologies your laptop has available.  ACPI throttling:
> > > yes, SpeedStep: mostly yes, ACPI performance states: no.
> >
> > ACPI performance states (IO only though) should be ok, no?
> 
> There's no way to read the current ACPI performance state value.  The only
> thing you can do is set a performance state and validate that it
> succeeded.
> 

Indeed, but at least you can have some older technology supported though.
Ok, most of them are now completely understood, even though you can only
have at most beta support due to lack of documentations from vendors if
you do not want IO based acpi performance support.  Also, you may
want to add some stuff for configuration only purpose in order to simplify
things (like in centrino platform for example), or to get configuration for
powernow-k7 when the legacy method fail.

-- 
Ducrot Bruno

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