cpufreq not working

nickptar · 06-15-2006, 01:35 PM

I have an IBM Thinkpad R40 with a 2GHz P4 and Intel chipset. I'm using Mandriva 2006 with a custom-compiled kernel 2.6.16.20. The freq_table, speedstep_lib, and p4_clockmod modules are loaded, and didn't display any error messages on loading. The contents of all files in /sys/devices/system/cpu/cpu0/cpufreq are:

Code:

affected_cpus: 0
cpuinfo_cur_freq: 2000000
cpuinfo_max_freq: 2000000
cpuinfo_min_freq: 2000000
scaling_available_frequencies: 2000000
scaling_available_governors: userspace performance
scaling_cur_freq: 2000000
scaling_driver: p4-clockmod
scaling_governor: userspace
scaling_max_freq: 2000000
scaling_min_freq: 2000000
scaling_setspeed: 2000000

As you might guess, I can't set the frequency to anything other than 2 GHz. I used to be able to set it down as far as 250 MHz, but that stopped working more or less randomly (I don't recall it coinciding with a kernel upgrade or any other major change). What's keeping it from working?

LazyP · 06-15-2006, 06:13 PM

Well it seems that you have two governors available: userspace and performance.
Performance sets the frequency statically to the highest possible value so you have only one choice: userspace.
You need some kind of deamon that will decrease your CPU's frequency. On my AMD64 i've used "powernowd" for months with no problem at all and AFAIK it works fine with Intels too. Consider using it. Alternatively you can recompile the kernel and choose the "ondemand" governor (this is what I have right now).

nickptar · 06-15-2006, 09:13 PM

As I said, the current governor is 'userspace'. I should be able to set the frequency manually by echoing to scaling_cur_freq, but I can't. powernowd does nothing, and neither does the ondemand governor.

LazyP · 06-16-2006, 03:29 AM

Then it may be a BIOS issue. In Athlons for example you have to enable Cool 'n' Quiet. The same feature is called sth like CPU throttling for P4.
Also try to echo values lower than 2000000 to scaling_min_freq and/or cpuinfo_min_freq and a list of frequencies to scaling_available_frequencies.
The same files for me look like that:
affected_cpus: 0
cpuinfo_cur_freq: 1000000
cpuinfo_max_freq: 2000000
cpuinfo_min_freq: 1000000
scaling_available_frequencies: 2000000 1800000 1000000
scaling_available_governors: ondemand performance
scaling_cur_freq: 1000000
scaling_driver: powernow-k8
scaling_governor: ondemand
scaling_max_freq: 2000000
scaling_min_freq: 1000000

There are also two directories called "stats" and "ondemand". The latter holds files that configure the ondemand governor