Re: Build PST for AthlonXP

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

On Thu, Feb 05, 2004 at 08:17:53AM +0100, Lukas Schrangl wrote:
> > On Wed, Feb 04, 2004 at 11:45:25AM +0100, Lukas Schrangl wrote:
> > > Hi!
> > > 
> > > I don't know wether this is the right mailinglist for my problem, but at
> > > least I think here are some people who can help me.
> > 
> > Correct, the mailling list is the CPUFreq mailing list..
> > 
> > > Maybe someone remembers my problem: I have a AMD Athlon XP 2600+ mobile
> > CPU
> > > but neither ACPI- performance states nor cpufreq/powernow-k7 (no PST
> > matching
> > > this cpuid) do work.
> > 
> > Retrieving configuration from ACPI is a work in progress.  I do have
> > some experimental patch for, but not publically available yet
> > (it depends on others patches from Dominik, I'm not sure if that OK by
> > now).
> > 
> > > Recently I browsed a bit through the powernow-k7 source and have now an
> > idea
> > > how it works. It shouldn't be too difficult to set up my own PST for my
> > CPU,
> > > should it?
> > 
> > Well, not so, especially if you can retrieve the configuration for the
> > different
> > states.
> > The key is the control word, in the _PSS packages.
> > 
> > For example, suppose you have that:
> > 
> > Processor(..) {
> > 	...
> > 	Name (_PSS, Package () {	/* this may be a method, btw */
> > 		Package () {
> > 			0x0352,
> > 			0x61A8,
> > 			0x7D,
> > 			0x009C414B,	/* that the control. */
> > 			0x014B
> > 		},
> > 		Package () {
> > 			...,
> > 			...,
> > 		}
> > 	})
> > 
> > For the first one, this is 0x009C414B.
> > The layout seems to be:
> > bit 0-5: FID,
> > bit 6-10: VID,
> > bit 11-30: SGTC (or in other word 'latency' in 10 time micro second)
> > bit 31-32: reserved.
> > 
> > Note that this is *not* confirmed by AMD people.
> > 
> > > I know about FIDs and VIDs and what they are good for, but can anyone
> > > explain me the structure of a PST and the PSB (links to some documents,
> > ...)?
> > > The second thing: I could get the cpu- frequences that seem work (for my
> > > FIDs) from my SSDT, but how can I calculate the voltage (for the VIDs)
> > matching
> > > the frequency, if there are only the mW given in the SSDT?
> > > 
> > 
> > BTW, I send to CPUFreq ML yesterday a patch in order to get a sysctl
> > interface for overwritting a powernow k7 table.
> > 
> > http://www.poupinou.org/cpufreq/powernow-k7/
> > 
> > Cheers,
> > 
> > -- 
> > Bruno Ducrot
> > 
> > --  Which is worse:  ignorance or apathy?
> > --  Don't know.  Don't care.
> > 
> > 
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> > 
> 
> Sysctl? I just hard-coded a PST (thanks to your hint with the SSDT-
> controldwords) and patched powernow-k7.c to make the driver use that PST instead of
> BIOS PSTs. What shall I say? It simply works ;)

I do not doubt that it work, just that the sysfs things is generic for
everybody (even if the driver is correctly loaded in fact), and then
you don't have to worry about to patch the kernel anymore.  Just
a little rc-script to write...

> PS.: I found one of the FIDs in the SSDT to be false, so maybe it's not save
> to read the powernow- states from ACPI.

Let me guess.  The one that is before the latest state, and actually
you meant the VID value which is a little too high?

If that's the case, it should be safe to go, but yes, I
have to workaround that though.  But if that's really the FID
which is wrong, well, I will be gratefull to get a report.

I saw also one example where the maximum speed was missing (and
of course, there is no BIOS PST)...

Note also that the acpi things is only done if and only if
the laptop is DMI blacklisted (and ACPI processor is compiled,
of course).

-- 
Bruno Ducrot

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


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