Talk:How to make use of Dynamic Frequency Scaling
Contents
CPUfreq "stuck"
Using the "acpi-cpufreq" and "processor" modules, I can use the performance and ondemand governor with great success on a T43, and it switches between 2.1 GHz and ~700 MHz without incident. However, sometimes the processor becomes "stuck" at ~700 MHz, and when I switch to the performance governor "cat /proc/cpuinfo" notes it is still at ~700 MHz.
I have not been able to precisely reproduce these conditions, but they have happened several times. It is cured by a reboot. I'm not running any userspace frequency governers. Anybody else experienced this peculiar behavior? gsmenden 11:20, 10 JAN 2006 (CEST)
I had something similar on my T43. It seems that BIOS interfers with cpufreqd's operation. In the end I set BIOS to "maximum performance" when the laptop is on AC, and let cpufreqd keep track of the speed. It seems to work for me (T43, 2669, 2.6.15-kernel)
CPU Speedstep management activation
I could not find the "processor" and "acpi-cpufreq" modules, thus leading to an empty /sys/devices/system/cpu/cpu0/ and preventing to set cpu throttling. I found the speedstep-centrino module which enables the feature. Environment : X41 (Pentium M), Debian Sid with custom 2.6.12 kernel. Is the Debian part of the article outdated ? Hope this helps, Vincent
speedstep-smi for T22
I had to use the speedstep-smi driver for my T22, not the speedstep-ich driver as stated in the how-to. Thomas
Yes, it was a mistake. Thanks for the note. Wyrfel 21:49, 27 Oct 2005 (CEST)
Extremely low freq on a T22
About an hour ago I made Speedstep work on a T22 running Ubuntu Breezy (5.10). Before that I had the machine randomly boot at 700MHz or 900MHz. That is nothing special. But, earlier today, when I booted it, it was running at 187MHz, according to both /proc/cpuinfo and Gnome's CPU frequency applet. It also took about 4 times as long to do some CPU-intensive processing than usually (grepping and sorting a known amount of text), so I'm still thinking that my Thinkpad really was running at 187MHz until I rebooted it.
Has anyone else noticed anything like this? Is there a way to replicate this behavior? Is there a way to "enable" this "step"?
-- _sd
Yes, i brought my X20 down to similarly low frequencies also with Ubuntu. I think it's possible through ACPI throttling, but I'm not sure if that was actually how i did it.
Wyrfel 23:51, 9 Jan 2006 (CET)
