Powersaved

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Revision as of 19:57, 12 November 2006 by FrankTM (Talk | contribs) (Step 1: CPU Stepping)

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Goals

The goal of this article is to get cpu speedstepping. Also suspend to ram and possibly to disk too, both possible for standard (non-root) users. This should all be provided by the powersaved daemon.

Required packages

  • extra/powersave
  • extra/gnome-power-manager (or kde equivalent)(optional)

Install by doing:

pacman -Sy powersave gnome-power-manager

Post-installation steps

  1. Add your user to the power group (e.g. by editing /etc/group).
  2. Put powersaved into the deamons array in /etc/rc.conf, or manually start the deamon (/etc/rc.d/powersaved start with root privileges).
  3. Run gnome-power-manager (if applicable). gnome-power-preferences can be used if you cannot see the program icon in the system tray by default.

Step 1: CPU Stepping

When you started for the first time, the powersave daemon will give you a warning like this:

enter 'powernow_k8' into CPUFREQD_MODULE in /etc/powersave/cpufreq.
this will speed up starting powersaved and avoid unnecessary warnings in syslog.

Sometimes auto detection of the right module fails. So if you are sure you need a module different from the one provided you should use that instead.

You should edit the /etc/powersave/cpufreq file as root and adjust the following parameters:

  • CPUFREQD_MODULE
  • CPUFREQ_CONTROL
$editor /etc/powersave/cpufreq

Set CPUFREQD_MODULE to the module the auto detection found, or the one you think you need. I'd like to set CPUFREQ_CONTROL to ondemand.

Now, when you restart the powersave daemon, it should start without warnings.

To test if you actually now have speedstepping I use a gnome tool, which you can add to your panel. It's called CPU Frequency Scaling Monitor.

Step 2: Suspend to ram (suspend2ram)

If using gnome-power-manager, you can click Suspend on the system tray icon. From console, run:

powersave -u

Problems can be diagnosed in /var/log/suspend2ram.log

Step 3: Suspend to disk (suspend2disk)

In order to get suspend2disk to work (this is labeled as hibernate by Gnome convention), you will need to edit your GRUB menu.lst file (e.g. /boot/grub/menu.lst).

Add resume=/dev/swap as the kernel argument to menu.lst, where swap is your swap device.

E.g.

# (0) Arch Linux
title  Arch Linux  [/boot/vmlinuz]
root   (hd0,2)
kernel /boot/vmlinuz26 root=/dev/hda3 resume=/dev/hda4 ro
initrd /boot/kernel26.img

Reboot before you attempt to use the feature.

You can suspend to disk by clicking on Hibernate in gnome-power-manager menu or in console by:

powersave -U

Problems can be diagnosed in /var/log/suspend2disk.log file.

Known issues