cpufreq configuration problems

FliesLikeABrick · 08-14-2005, 09:09 AM

As I was setting powernowd up on my Thinkpad T42, I encountered a small thing where it wouldn't
switch correctly as I changed from AC to battery. It was reccommended
that I upgrade to 0.96 instead of 0.90.

I downloaded and installed 0.96 and now powernowd will not start:

Quote:

root@ryanlc1:/opt/powernowd/powernowd-0.96 # powernowd
powernowd: PowerNow Daemon v0.96, (c) 2003-2005 John Clemens
powernowd: Found 1 cpu: -- 1 thread (or core) per physical cpu
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq: No such file or directory
PowerNowd encountered and error and could not start.
Please make sure that:
- You are running a v2.6.7 kernel or later
- That you have sysfs mounted /sys
- That you have the core cpufreq and cpufreq-userspace
modules loaded into your kernel
- That you have the cpufreq driver for your cpu loaded,
and that it works. (check dmesg for errors)
If all of the above are true, and you still have problems,
please email the author: clemej@alum.rpi.edu

Insight? I hope to use linux as the primary OS on the laptop, but
cannot do so without decent power conservation :-/

The laptop is an IBM T42 with a pentium M 1.8ghz (dothan). The kernel
is version 2.6.10-5-386 and /sys is mounted correctly.

/sys/devices/system/cpu/cpu0/ exists but the cpufreq subfolder does not.

I am led to believe that all necessary modules are loaded (considering
it ran 0.90 fine for that short period of time before I upgraded), but
any information on how to check the modules or insert the necessary
ones would be helpful. I am not sure which modules are necessary for
this processor for cpufreq, so information on that might help as well.
It seemed to run powernowd 0.90 fine, but for some reason will not run
0.96. When I try to go back to 0.90, it still will not work (aka 0.90
does not work anymore).

lsmod | grep cpu returns nothing, though.

The sooner I get this working, the better. I will keep looking around.

I hope that this is enough information to help you narrow down the
problem and appropriate solution,

basileus · 08-16-2005, 12:41 PM

Check my webpage at

http://users.utu.fi/sjsepp/linuxcompaqarmada100s.html

on how to enable powernowd. Please note that there different cpufreq modules for different processors. The module I use is "powernow_k6" - your may differ.

Modules can be loaded with "modprobe modulename" - as root of course. You said you tried "lsmod|grep cpu"... it should return a bunch of module names starting with "cpufreq_xxx".

FliesLikeABrick · 08-16-2005, 05:18 PM

that page doesn't tell me anything, it only has a couple sentences about it. i need to know what module(s) are needed for a pentium M (dothan 1.8ghz) and what cpufreq_xxx modules are needed, because i can't find this information just about anywhere else.

pafrica · 09-01-2005, 04:37 PM

Hi,

I've been having the same problem. I checked out the syslog and it said something about a missing config file: /etc/cpufreq.conf so I created my own. Cpufreq still wouldn't start, however. Although this time, it's telling me cpufreq drivers need to be loaded for cpu0. I'll look into it some more and tell you what I've come up with.

TFMegatron · 09-01-2005, 08:28 PM

In the kernel go to:

/power management options/cpu frequency scaling/

Activate that either Y or M

Then pick the userspace governor and Intel Enhanced SpeedStep
That should have also picked use acpi tables and built in tables.
Also choose your default governor to userspace.
Recompile and you should be good.

pafrica · 09-01-2005, 08:41 PM

TFMegatron,

I just did a kernel recompile with cpu frequency scaling, powersave, ondemand an userspace governors, enhanced speedstep support and frequnecy table all built into the kernel and now cpufreq runs fine. Prior to this, only cpu frequency scaling was built into the kernel and everything else was modularized. Cpufreq doesn't seem to work with that kind of config. I want the governors and speedstep support as modules, however. Am I missing something?

TFMegatron · 09-01-2005, 09:18 PM

Quote:

Modules can be loaded with "modprobe modulename"

Did you try to load them manually?

pafrica · 09-01-2005, 09:55 PM

I've tried modprobe-ing the governors (i.e. any of powersave, ondemand and userspace). They show up when I lsmod but the problem was there was no cpufreq directory under /sys/devices/system/cpu/cpu0.

It was odd because it appeared the governors could be loaded and yet the cpufreq driver (acpi_cpufreq which is built into the kernel) wasn't doing its job.

TFMegatron · 09-01-2005, 10:39 PM

You needed to also modprobe the driver. The speedstep one. You must have acpi cpufreq, your speedstep, and lastly the governor.

pafrica · 09-01-2005, 11:18 PM

Thanks mucho, TFMegatron. It works like a charm now. I'm trying to get cpufreqd (the daemon) to work. Do you have any experience with it? I want to be able to set the voltage too like i can in win XP. I know I can do it using cpufreqd but is that also possible through just cpufreq?

TFMegatron · 09-02-2005, 01:39 AM

Sorry I am not familiar with that. Your welcome though.

kWzTa · 09-24-2005, 01:36 AM

You should try recompiling your kernel with the following option:

Code:

-> Power management options (ACPI, APM)
   -> CPU Frequency scaling  
      -> <*>  CPU Frequency scaling
         ---   CPUFreq processor drivers
         <*>  ACPI Processor P-States driver

Without it, the directory /sys/devices/system/cpu/cpu0/ remains empty.

pafrica · 09-24-2005, 01:43 AM

Thanks kwzta. Cpufreq works for me now. Do you know anything about undervolting the processor?

kWzTa · 09-25-2005, 07:25 AM

Unfortunately, i don't know much about it.