Difference between revisions of "Powersaved"

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The '''<tt>powersaved</tt>''' package has been replaced by '''[[Pm-utils]]''' (hibernate/suspend) and '''[[Cpufrequtils]]''' (CPU frequency scaling).  Please see those wikis for up-to-date information.

Revision as of 15:16, 29 August 2007

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The powersaved package has been replaced by Pm-utils (hibernate/suspend) and Cpufrequtils (CPU frequency scaling). Please see those wikis for up-to-date information.


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.

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:

$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.

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

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.


# (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

  • Sometimes auto detection of cpufreq modules doesn't detect the proper module. Users are advised to check if the correct CPU module has been loaded after installation
  • ATI video card owners may need to disable the framebuffer in order for suspend-to-ram to work properly. Add vga=0 to the kernel options in /boot/grub/menu.lst