Re: HP nc6400 v.03 or v.05 laptop ACPI fails after reboot, works again after booting windows

Frank Ursel
2006-12-16T08:18:02Z

On Sat, Dec 16, 2006 at 02:59:53AM -0500, Lincoln Baxter, III wrote:
> Pavel Troller wrote:
> >Hi!
> >
> >Try the following:
> > cat /proc/acpi/processor/*/power in the following situations:
> > 1) After loading the processor module being on the battery,
> > 2) After loading the processor module being on AC,
> > 3) After disconnecting the AC,
> >and compare the results. I think that for 1), you will see more C-states
> >than
> >for 2) and that possibly the missing C-states are not added for 3).
> >
> And the reason the hum seems to go away when AC is plugged back in, is
> because it switches to C2.
>
> I have this question, however. While the CPU is powered down,
> /proc/cpuinfo still shows the full frequency of the chip, at 1823Mhz.
> When I enable cpufrequtils, and clock down the processor, there is no
> change in noise or power consumption, it's still noisy, and it's still .
> If this is the case, then why bother with cpufrequtils in the first
> place... also... I still have the question of why doesn't this happen in
> windows? What power state is windows running in to get as much or more
> battery life, and still have no humming noise?
>
> It seems like the processor module must be doing something that isn't
> quite right. I heard that there's supposed to be a C0, and a C4 power
> state for the core duo processor, but I don't see those in the list of
> options. Any ideas as to why they don't show up?

As far as i know, the humming appears in windows too. I tested it with
the RMClock utility and on my laptop, switching to C4 was making the
humming. But every other C-State was quite. You should tune the timing
frquencies, like Pavel pointed out.

But i'm curios, why on linux the C4-State does not show up. The maximum
working C-State on my system, on AC or battery is C3. Is there any
hidden switch to enable it?

with regards, frank