Power saving configuration on Mandriva Linux
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Contents |
Cleaning
A dense layer of dust between your fan and you CPU heat sink can make your CPU very hot, and, by reaction, very slow (up to 5 times slower in my case) and your fan very noisy. Eventually, our computer began to stop suddenly when it would get too hot. Close the gaping slots openings at the back of your desktop you don't use anymore if any (with sellotape if there is nothing else), and clean your computer inside twice a year. Depending on your contract, it's possible your garantee get void if you open the box. In such a case, consider having your computer cleaned by your reseller.
Before cleaning your computer, unplug it from the mains. Synthetic clothes may carry static electricity, dangerous for your computer. Prefer cotton to clean it.
Keeping the room cool
The hotter is the room your computer is in, the more difficult it is to evacuate the heat, and the more energy will be used for that. Keep your computer room cool and well ventilated.
Suspend
Userland support
pmsuspend interface
pmsuspend is the official suspend interface, it is provided by the suspend-scripts package. It takes care of shutting down services and removing modules before going to suspend and restart those things after coming back. The configuration file is /etc/sysconfig/suspend.
Usage: /usr/sbin/pmsuspend ACTION Suspend to memory: /usr/sbin/pmsuspend [memory|ram|suspend] Suspend to disk: /usr/sbin/pmsuspend [disk|hibernate]
Frontends
These applications call pmsuspend to trigger the suspend:
- klaptop
- gnome-power-manager
- any application using HAL to suspend
Suspend sequence
hibernate interface
hibernate is a script supporting software suspend 2. Suspend 2 provides some additional features that are currently not supported by software suspend 1. The configuration files for hibernate can be found in /etc/hibernate/. Help can be found by typing
man 5 hibernate.conf
at the command prompt, after installing the hibernate package.
Software Suspend 1 (standard kernel, kernel-multimedia, kernel-tmb)
Fully supported in the suspend-scripts package.
Software Suspend 2 (kernel-multimedia only)
Requires the hibernate package (from contrib).
Kernel support
The standard Mandriva kernel has Software Suspend 1 enabled. Multimedia kernel (in contrib) has Software Suspend 2 enabled by default starting from version 2.6.16 and up Pre-built rpm and srpm multimedia kernels are on cooker, versions for 2006 may be found at:
APM vs ACPI
CPU frequency
CPU frequency scaling modules
The cpufreq initscript probes power saving modules at boot and loads them. This is not the proper way to do it, because the cpufreq services runs the detection at each boot. harddrake should better modify some /etc/modprobe.preload.d/cpufreq file when the processor is changed.
CPU frequency scaling programs
- klaptop
- cpufreqd
- cpu_freq_throttle applet
- "CPU Frequency Scaling Monitor" applet in GNOME (cpufreq-applet)
You can install one of the them in 
Configure your computer → Software management → 
Install & Remove Software. Then you need to make it running, still in Mandriva control center → System → 
Manage system services by enabling or disabling them then, on the line of the program, click on the button "Start" and check the box "On boot" if you want the program to run at each boot.
cpufreq
cpufreqd is usually used with cpufreq, which comes with 2 commands: "cpufreq-info" and "cpufreq-set". The latter can only be run by root, the superuser. The different modes of CPU frequency scaling are called "governors" and are explained there. To have cpufreq work with cpufreqd, and so the frequency scaling managed by Linux, you should set the gouvernor to "cpufreq_userspace". To do so, go to Application launcher menu → Tools → Konsole terminal, there log as root:
and then, as root, type
to have your CPU #0 managed by cpufreqd. If you have a second CPU, #1, then type also
etc. Check the result by launching
If everything is OK, leave your root rights:
Various hardware compatibility list
Power saving compatibility list
See also
Instructions for using a custom DSDT (Differentiated System Description Table) are available at Hardware. This provides a means for getting ACPI if ACPI isn't working with your kernel.
