Selecting CPU frequency on Asus P4M laptop

Selecting CPU frequency on Asus P4M laptop

[Måns Rullgård]

I have an Asus M2E laptop with a 1.8 GHz P4M CPU.  Using the 'acpi'
cpufreq driver, I can select between 1.8 GHz and 1.2 GHz, thereby
changing the power consumption.  If I boot the machine with the AC
adapter disconnected, it starts off at 1.2 GHz.  After that, I can
lower it to 800 MHz using cpufreq.  In short, cpufreq will be able to
choose among one of two pairs of frequencies, which depend on the
status of the AC adapter at boot time.

Is there any way to change which of these will be used after booting?

-- 
Måns Rullgård
mru@kth.se

Re: Selecting CPU frequency on Asus P4M laptop

[Marco Roeland]

On Thursday November 27th 2003 Måns Rullgård wrote:

> Is there any way to change which of these will be used after booting?

Have you already tried (as a module, *not* builtin) the SpeedStep
clockmod driver (CONFIG_X86_P4_CLOCKMOD=M) or, if your Southbridge is an
ICH[234], the ICH driver (CONFIG_X86_SPEEDSTEP_ICH=M)?

You might then always have access to the maximum speed, and reduce
according to need of usage to something lower.
-- 
Marco Roeland

Re: Selecting CPU frequency on Asus P4M laptop

[Måns Rullgård]

Marco Roeland <marco.roeland@xs4all.nl> writes:

> On Thursday November 27th 2003 Måns Rullgård wrote:
>
>> Is there any way to change which of these will be used after booting?
>
> Have you already tried (as a module, *not* builtin) the SpeedStep
> clockmod driver (CONFIG_X86_P4_CLOCKMOD=M) or, if your Southbridge is an
> ICH[234], the ICH driver (CONFIG_X86_SPEEDSTEP_ICH=M)?

I've tried them all.  Only acpi and p4-clockmod load successfully.

-- 
Måns Rullgård
mru@kth.se

Re: Selecting CPU frequency on Asus P4M laptop

[Måns Rullgård]

mru@kth.se (Måns Rullgård) writes:

> I have an Asus M2E laptop with a 1.8 GHz P4M CPU.  Using the 'acpi'
> cpufreq driver, I can select between 1.8 GHz and 1.2 GHz, thereby
> changing the power consumption.  If I boot the machine with the AC
> adapter disconnected, it starts off at 1.2 GHz.  After that, I can
> lower it to 800 MHz using cpufreq.  In short, cpufreq will be able to
> choose among one of two pairs of frequencies, which depend on the
> status of the AC adapter at boot time.
>
> Is there any way to change which of these will be used after booting?

Update:

I ran a speed test, "openssl speed", in the various modes, and it gave
the same results whichever way the machine was booted.  It appears to
be reporting/detecting incorrect values when the AC adapter is
unplugged.  Switching speeds with cpufreq does change the actual speed
of the CPU.

-- 
Måns Rullgård
mru@kth.se