Re: Mobile Intel Celeron 2.0 GHz with ICH4 bridge

["Keld Jørn Simonsen" <keld@dkuug.dk>]

On Tue, Feb 24, 2004 at 09:22:22AM +0100, Dominik Brodowski wrote:
> On Mon, Feb 23, 2004 at 10:36:19PM +0100, Keld Jørn Simonsen wrote:
> > Hi
> > 
> > I have an Acer Travelmate 233 and I am trying to save some battery
> > power. Is that possible with cpufreq? 
> > 
> > The CPU is a Mobile Intel Celeron 2.0 GHz and the southbridge is an
> > Intel 82801DB 845G/GL Chipset ISA Bridge (ICH4)
> > 
> > I run Mandrake 10.0 RC1 with kernel 2.6.2 and cpufreq 1.0.1,
> > unfortunately I get the following message:
> > cpufreq: Intel(R) SpeedStep(TM) for this chipset not (yet) available.
> > Is this because I am running an outdated version of cpufreq,
> > or just because the CPU is not recognized properly?
> 
> The problem is that you have a Mobile Celeron which does not support
> SpeedStep. All you could get from cpufreq is Clock Throttling,
> (p4-clockmod), but this won't save you much in terms of battery power.

OK, understood.

> > Are there other ways to save power with this machine, on the CPU?
> ACPI processor support with working C1 and C2 idle states [check
> /proc/acpi/processor/*/power ]

As I can see it, my system already goes in autohalt. The normal 
system power drainage is about 38 W, but I can measure the power use to
about 18 W when I do nothing, (with my harddisk in sleep, and my screen
turned to lowest intensity).

I understand that throttling is actually putting the CPU off power.
I would like to be able to shut off just the CPU, getting a savings of
about 7,5 W. Is this possible, is there a way to shut off the CPU while
having the screen and ram on power? What commands should I issue, or is
this something I need to make a program to do?

The idea is to shut off the CPU after it being idle for about a second,
and resuming the operation next time I touch the keyboard or the mouse.
1 second would allow normal typing or normal mouse movement to perform
as usual, while having the screen lit would give the impression of 
the machine being on. Going from 18 W to about 11 W would give me about
2 hours more of battery time.

best regards
keld