Re: Re: DSDT Change (Compaq Presario 2100)

[Andre Eisenbach <andre-+hZUvIEKc2q1Z/+hSey0Gg@public.gmane.org>]

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Am Samstag Mai 29 2004 11:53 schrieb Erik Meitner:
> > Well, tonight, while recompiling the DSDT a few times to remove warnings
> > and errors, I stumbled across this (in method SMSL
> >
> > If (0x01)
> > {
> > 	Store (\_SB.PCI0.ISA.EC0.TTDC, TRDC)
> > 	Store ("AC remove! Set Throttle Duty Cycle ---: ", Debug)
> > 	Store (TRDC, Debug)
> > 	Store (0x01, TREN)
> > }
>
> The DSDT for my laptop has the exact same code.

That piece of code is the state cange code (i.e. when you unplug the AC cord). 
There is another place you need to change, which initializes the behaviour 
when you boot with the power cable already unplugged.

The method is _REG. Here is the code

                                Store (0x01, \_SB.PCI0.PMU.CRUN)
                                If (0x01)
                                {
                                    Store (\_SB.PCI0.ISA.EC0.TTDC, TRDC)
                                    Store (0x01, TREN)
                                }

Once again change "If (0x01)" to "If (0x00)".

> > In any case, I changed "If (0x01)" to "If (0x00)" and voila, I am typing
> > this email from KDE with the power cord unplugged - no slowdown at all.
>
> I have verified that this works for my machine also.

Thats great news!

> Am I correct in assuming that TREN is "Throttle Enable"(boolean value)
> and TRDC is "Throttle Duty-cycle"? What other TRDC values might make
> sense other than 0x0 ?

I think you're right about TREN and TRDC. 
That method of throttling the CPU is not a good method apparently. It also 
doesn't save battery (at least for me). Instead, use "PowerNOW" if you have 
an AMD chip. It's built into the 2.6+ kernels (cpufreq) and works like a 
champ for me.  And unlike the DSDT based throtteling, you can control it!

Cheers,
    André

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