Need to unload/load some modules in order to get cpu-scaling working

[Pablo Castellano]

By default I can't change the cpu frequency when my system is just booted. It's stuck to 800MHz
My supported frequencies are 800MHz, 1,6GHz, 1,8GHz and 2,0GHz.
I use the applet for gnome-panel and I can click 1,6, 1,8 and 2,0 but it never changes, it continues stuck at 800MHz.

Workaround:
********************** WARNING!! Use it at your own risk. Read comments from gali98. **********************
I have found a solution to make it work. If I open a terminal and type (as root obviously):
modprobe -r cpufreq_stats; modprobe acpi_cpufreq; modprobe cpufreq_stats;

I get:
FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.27-3-generic/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): Device or resource busy

acpi_cpufreq is not loaded, but CPU SCALING WORKS!!

This is quite wierd.
To make it weirder: if my laptop is connected to the current, cpu scaling works without any workaround but if I disconnect it, cpu scaling doesn't work.

Everytime that my system is rebooted I have to do it to get cpu scaling working with batteries.

System:
Ubuntu 8.10 fully updated (18 sept)
Laptop is HP Pavilion tx2000 model (some other users have reported this issue in ubuntuforums too).

logs.tar.gz includes:
uname -a
version_signature
dmesg
lspci -vvnn
dmidecode
/proc/acpi

[gali98 (korylp)]

Confirmed Bug and Work around on HP Pavillion tx2000z. (same output about module)
Kory

[gali98 (korylp)]

Can confirm.. See comment...

[gali98 (korylp)]

Do not use this workaround!!!!
It kills power managment and temperature monitoring leading to a poweroff because of high temperature.
My CPU got very hot after using the workaround, and after 20 minutes shut off without warning.
Could cause serious damage....
Kory

[Pablo Castellano (pablocastellano)]

That's strange, it has always worked for me :-/

[Oszkár Ocsenás (ocsenaso-gmail)]

Same on AMD Turion(tm) 64 X2 Mobile Technology TL-50 in Amilo Pa1510.
I can't change cpufreq, and system can't automatic too.
I typed cat /dev/urandom > /dev/null in 4 terminals, but cpufreq works only in 800MHz.
Supported freq's: 800, 1.6 Ghz

Fully updated Ubuntu 8.10 (15 oct)
In /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq shows 800MHz, scaling_min_freq shows 800 too.
HTOP shows 100% cpu load all two cores.

saint@terminus:~$ lsmod | grep powernow

powernow_k8 23684 1
freq_table 13568 3 powernow_k8,cpufreq_ondemand,cpufreq_stats
processor 47800 2 powernow_k8,thermal

saint@terminus:~$ sudo modprobe acpi_cpufreq

FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.27-7-generic/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): Device or resource busy

saint@terminus:~$ uname -a

Linux terminus 2.6.27-7-generic #1 SMP Tue Oct 14 18:38:59 UTC 2008 x86_64 GNU/Linux

If I disable powernowd on boot, cpu works 1.6 GHz fine.

I hope this will help you

[gali98 (korylp)]

On the tx2000z, I discovered after updating the bios to the new version that there is an option that will fix this.
In the Bios you can select battery performance. If you select the option "Performance" (the default is power-saver or something like that) then the cpu will scale up when on battery power, and you can also select what you want it to scale to.
I am on Intrepid and on the tx2000z so that may make the difference.
Kory

[Oszkár Ocsenás (ocsenaso-gmail)]

For me:

saint@terminus:~$ sudo modprobe acpi_cpufreq

FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.27-7-generic/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): Device or resource busy

was solved the problem.
It's interesting, that lsmod don't show the acpi_cpufreq module, but freq-scaling works now manual scaling works too.

saint@terminus:~$ lsmod | grep cpufreq

cpufreq_ondemand 16400 1
cpufreq_userspace 12420 0
cpufreq_powersave 10368 0
cpufreq_stats 14468 0
freq_table 13568 3 powernow_k8,cpufreq_ondemand,cpufreq_stats
cpufreq_conservative 16392 0

saint@terminus:~$

[gali98 (korylp)]

There was an option in the bios of my tx2000z (you may need to update) about battery performance.
If you set it to high performance, the cpu can scale up while on battery.
Kory

[Brad Figg (brad-figg)]

This bug was filed against a series that is no longer supported and so is being marked as Won't Fix. If this issue still exists in a supported series, please file a new bug.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.