Hi

I'm sure guides exist for doing this, but I though I'd ask here in case someone knows of a guide that applies easily to Slackware 12.2

I would like my laptop to switch the CPU into some low-energy-usage mode when it's not being used (say when the screensaver comes on). What are the commands I need to run?

And is there a hook for the screensaver to run this script of mine when the screen is turned off?

Thanks in advance

Hi,

You should look at 'How to suspend and hibernate a laptop under Linux'.

This link and others are available from 'Slackware-Links'. More than just Slackware® links!

Hi onebuck

Thanks for the link, but I already set up suspend and don't much care for hibernate.

What I'd like to do is turn down my CPU clock speed while the system is running, so it uses less power and makes less heat.

Check out cpufreqd and cpufrequtilites, Also make sure you have power saving enabled in your kernel and that it is set to change on the fly. (ondemand/conservative/ or userspace)

Hm, cpufreqd won't compile even though cpufrequtilites installed, and I tried one other simpler utility that compiled but wouldn't run because something was missing in /sys

I guess the stock slackware kernel is missing something. And I hate recompiling kernels cause I always find one way or another to screw up

Maybe I'll have some time one day to try it, for now I'll assume that Slackware isn't capable of this feature out of the box and live with that.

Use the ondemand cpufreq governor - you can set it from rc.local or some such.

No, not out of the box. .

Not full-blown tutorials, but perhaps the following will help:

Enabling CPU Frequency Governors
Green Computing

Reducing frequency is a good start. Reducing core voltage is better. Electrically, energy consumption is proportional to frequency but exponentially related to voltage.

First thing to do is verify the BIOS is configured correctly. Caveat: Not all CPUs support such features.

Regarding CPU governors, loading only the ondemand governor usually is the best method. All of the governors can be loaded concurrently, but only one can be used at any one time. So just load ondemand. To do that only requires editing rc.modules.

After loading the ondemand module, edit rc.local to automatically configure the /sys/devices/system/cpu/*/cpufreq/scaling_governor parameter.

Some of the recommendations provided by powertop (not part of the stock Slackware) requires recompiling the kernel.

The lm_sensors package is included in the stock Slackware but must be configured manually. The Conky utility is not included in the stock Slackware but is a great way to verify various energy saving features are functioning. The stock Slackware provides gkrellm.

Suspending and hibernating is challenging. There are a few threads here at LQ discussing the topic. Some people experience no issues, others never get suspend and hibernate to function properly.

Maybe play around with hdparm and the -S flag?