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Because of a noisy fan in my laptop, I need to change CPU frequency and for this task I need to load the appropriate kernel module.

The CPU in my laptop Acer TravelMate 4002WLMi is:

$ cat /proc/cpuinfo | grep "model name"
model name  : Intel(R) Pentium(R) M processor 1.60GHz

This article helped me to find the kernel module I need (my CPU differs only a little in frequency).

After the sudo modprobe speedstep_centrino command nothing happened.

echo $? returns 0.

Here is the output of lsmod and dmesg and other useful outputs.

Could you help me solve this problem (explain what's wrong with kernel modules and use the appropriate module for changing CPU frequency)?

OS: Lubuntu 11.10 (GNU/Linux 3.0.0-14-generic i686)

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Anything show up in dmesg and/or /var/log/messages or wherever your system logs are stored? – Mat Dec 7 '11 at 15:25
@Mat See question edit, /var/log/messages file is not present. – xralf Dec 7 '11 at 15:35
From the modprobe manpage: Usually modprobe only prints messages if something goes wrong. So, i would assume that the module was loaded fine. What does modprobe -v tell? Are the dmesg and lsmod output from the same session as the modprobe? – tohuwawohu Dec 7 '11 at 16:26
@tohuwawohu -v makes no difference. Yes, session is the same. – xralf Dec 7 '11 at 17:19
hmm - ok, 11.10 in fact doesn't log to /var/log/messages; but /var/log/syslog should be there - anything interesting there? If not, i fear i can't help any further. The blog entry you've linked did mention the acpi_cpufreq module - maybe this works? Are any modules blacklisted? – tohuwawohu Dec 7 '11 at 17:29
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1 Answer

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You should identify the list of modules loaded with lsmod command and verify whether the intended module has been loaded or not. Do it with sudo or as root and verify.

Can you check in from BIOS if there is anything you could do related to speedstep_centrino. Recently, speedstep-centrino module is deprecated in favor of acpi-cpufreq.

Can you check whats in the files here? Just a paste would do.

/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

Also, the entire content of /proc/cpuinfo.

BTW, about speedstep_centrino, here is what I found from net sources

Generally, SpeedStep will run at full speed while connected to AC, but drop to a slower speed on battery to save power. This can also be modified in the Power Management options so the system runs at full speed even on Battery.
Depending on your Power settings, the CPU may drop to a slower speed even on AC while it's idle (not really working hard), once you need the computing power, it'll automatically jump back up.    
Putting your Power Management option to ALWAYS ON, will have the CPU run at full speed always on AC and battery.

More from intel article at http://software.intel.com/en-us/articles/enhanced-intel-speedstepr-technology-and-demand-based-switching-on-linux/

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1) The output of lsmod is in the question. sudo makes no change 2) in BIOS is nothing about speedstep_centrino 3) acpi-cpufreq or acpi_cpufreq gives me the same results. The completation command on sudo modprobe acpi<TAB> gives me only acpi_ipmi, acpi_pad, acpiphp, acpiphp_ibm, acpi_power_meter so the may be something missing 4) I will paste the outputs to my question. – xralf Dec 9 '11 at 17:24
As you see, speedstep-centrino is deprecated and acpi* is much more functional these days. What is the problem with acpi module, do you see any error or lsmod does not show them again? load the acpi modules if they are not. – Nikhil Mulley Dec 9 '11 at 19:02
The problem with acpi* is the same as with speedstep_centrino (I can see nothing) (more in point 3 in above comment) – xralf Dec 9 '11 at 19:22

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