Re: cpufreq question
On Sun, Oct 02, 2005 at 02:13:01PM +0200, Arne Lange wrote:
> Mattia Dongili schrieb:
> >
> > can you provide the full output of cpufreq-info in both cases?
> >
>
> It needed some time but here it is:
>
> with ac:
> $ cpufreq-info
> cpufrequtils 0.2: cpufreq-info (C) Dominik Brodowski 2004
> Report errors and bugs to linux@brodo.de, please.
> analyzing CPU 0:
> driver: p4-clockmod
You may want to try with a different driver (speedtstep-centrino,
acpi-cpufreq) as p4_clockmod does save you anything, it doesn't
acually scale freq and voltage.
> CPUs which need to switch frequency at the same time: 0
> hardware limits: 213 MHz - 1.70 GHz
> available frequency steps: 213 MHz, 425 MHz, 638 MHz, 850 MHz, 1.06
> GHz, 1.28GHz, 1.49 GHz, 1.70 GHz
[...]
> hardware limits: 75.0 MHz - 600 MHz
> available frequency steps: 75.0 MHz, 150 MHz, 225 MHz, 300 MHz, 375
> MHz, 450 MHz, 525 MHz, 600 MHz
[...]
> For me it looks like something what happens before the Debian kernel
> starts. I think i've got to look further in my bios.
> Does anyone have another idea?
[...]
It looks to me that your bios (as does mine) decides the boot freqeuncy
depending on ac (you might also have some dmesg warnings, when attaching
and removing your ac plug, telling that the kernel and the system weren't
up to date wrt cpu frequency, do you? is that warning still there??)
1700/213=7.981 ~= 600/75=8.000
1700/638=2.664 ~= 600/225=2.666
the kernel reads the cpu frequency dividers without being aware of the
above facts and simply divides the boot frequency (thinking it's the max
value). AFAICT this is a bug in the kernel.
--
mattia
:wq!
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