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-   -   2.6.33.1 Intel Celeron M + cpufreq issues (http://www.linuxquestions.org/questions/linux-laptop-and-netbook-25/2-6-33-1-intel-celeron-m-cpufreq-issues-797041/)

wickedcracker 03-22-2010 07:36 AM

2.6.33.1 Intel Celeron M + cpufreq issues
 
Hello.
I have ASUS K40IJ laptop with Intel Celeron M (dual-core) CPU.
Recently I installed Gentoo Linux here with latest stable kernel from kernel.org (2.6.33.1).
I'm trying to configure power management here(battery now lasts around 3.5 hrs but I'd like it to act more).
Here is my builtin related modules dump:
Code:

root@host:/lib/modules/2.6.33.1# egrep '(clock|acpi|cpufreq)' modules.builtin
kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko
kernel/drivers/acpi/ac.ko
kernel/drivers/acpi/button.ko
kernel/drivers/acpi/fan.ko
kernel/drivers/acpi/video.ko
kernel/drivers/acpi/processor.ko
kernel/drivers/acpi/container.ko
kernel/drivers/acpi/thermal.ko
kernel/drivers/acpi/battery.ko
kernel/drivers/cpufreq/cpufreq_stats.ko
kernel/drivers/cpufreq/cpufreq_performance.ko
kernel/drivers/cpufreq/cpufreq_powersave.ko
kernel/drivers/cpufreq/cpufreq_userspace.ko
kernel/drivers/cpufreq/cpufreq_ondemand.ko
kernel/drivers/cpufreq/cpufreq_conservative.ko
kernel/drivers/cpufreq/freq_table.ko

Whenever I run cpufreq-info I get:
Code:

# cpufreq-info
cpufrequtils 005: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  no or unknown cpufreq driver is active on this CPU
analyzing CPU 1:
  no or unknown cpufreq driver is active on this CPU

Is there something I am missing on my kernel config?
p.s. This may be related since I've applied that patch so fixed an issue described here(weird it's present in 2.6.33.1): http://bugzilla.kernel.org/show_bug.cgi?id=15005
Thank you!

wickedcracker 03-22-2010 08:59 AM

okay, searching web for two days finally gave me this:
* http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=328528
Quote:

Well, p4_clockmod will not allow your notebook to run longer on battery
power. That's why "Pentium M" is so much more expensive than "Celeron M"s:
only Pentiums can do CPU frequency and voltage scaling.
from where I found this
* http://bugzilla.kernel.org/show_bug.cgi?id=12853
Quote:

p4_clockmod is not a power saving driver and not recommended so will not be
updating this.
Seems like this won't work.... :(
Can anyone confirm this or bring some clarity over this topic? Is that true that p4_clockmod won't save me even if I'd managed to set it up (because it fails to load throwing "Error inserting p4_clockmod (/lib/<pathtomodule>/p4-clockmod.ko): No such device")?

Maligree 03-22-2010 10:25 AM

Confirmed, I had a Toshiba M70 with a Celeron M on board. I was pretty sure that frequency scaling was possible, as the XP install that came with it claimed to be able to do so. Turns out that was a big fat lie (unless XP used some dark magic), as the Celeron M lacks Intel's SpeedStep technology (which handles the scaling).

Actually, if I remember well, the only difference between a Pentium M and a Celeron M is a smaller L2 cache size and no speedstep on the latter.

wickedcracker 03-22-2010 01:05 PM

Well that's what I've been said on IRC also. Thanks. I'll try to find another way to save battery time.

--
Update for those who might search for the same problem @ google, etc...:
When p4_clockmod fails to load, it will output the following to dmesg:
Code:

p4-clockmod: Unknown CPU. Please send an e-mail to <cpufreq@vger.k.o>


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