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Re: Power saving techniques



On 18.3.2006, T. M. said:

> Hi everybody, I have a PowerBook 12-inch, 1.5Ghz (System Profiler
> says it's a PowerBook 6,8).  I'd like to be able to save energy as
> much as I can while on the road; I'd like to know:
> 
> 1) Does my PowerBook support cpu scaling? How do I enable it? Can I
> even make it run at 500Mhz or so?

I think it runs at either half-speed or full speed.  You need to
enable cpufreq scaling in the kernel.  I'm not sure if the kernel
governors work on ppc or on this model.  I can say that I haven't had
any luck with them, but I haven't tried them lately.  If you use a
userspace governor, you'll of course need something in userspace to
control it.  


> > > > I've tried installing cpudyn and cpufreq but I don't
> understand how to configure it and understand if it's actually
> working.  Do I need both cpufreq and cpudyn?

No, one is enough.



> 2) I would really like to be able to suspend my computer.  I know
> that I can't suspend to ram because Nvidia (I have Nvidia Geforce
> 5200go) doesn't release drivers for PPC. (at least that's what I've
> been told) I'd love to be able to suspend to disk... can my
> PowerBook do that?  Does it need a particular kernel?

Yes.  I don't think it was possible with kernels before 2.6.12 and
there seems to have been a regression somewhere around 2.6.15, so any
kernel from the 2.6.12-14 series should work.  At least that's been my
experience on this powerbook.  The bad news is that you'll need a
newer kernel for wireless.

hope that helps.

-- 
Guy Yasko -- gyasko@gmail.com



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