22 FAQ

22.1 Something went wrong I'm not sure what

Have a look in /var/log/messages. All errors and warnings are logged there by default. You may additionally want to set up verbosity: set DEBUG variable to 7 or even to 15 in /etc/powersave/common and restart the powersave service/daemon to isolate the error. Messages are again logged to /var/log/messages.

22.2 I have ACPI enabled but buttons or/and battery states do not work as expected

or I have ACPI Errors in dmesg and /var/log/messages

or I don't see any battery information

If you experience ACPI related problems (normally logged in dmesg, or missing directories in /proc/acpi) (try: dmesg |grep -i acpi and watch out for errors).

Please visit the homepage of your laptop vendor and update your BIOS. Nag your vendor to stick to the newest ACPI specifications in their BIOS!

If they still occur you could try to find out why by debugging ACPI parts of your system (see ACPI_Debugging and to override your DSDT (see: DSDT).

22.3 CPU frequency does not work

See in the kernel source if your processor is supported: /usr/src/linux/Documentation/cpu-freq/* (You need to install the kernel-source package) and if you need a special module or module option (see Cpufreq). If you need a special module/option use following variables:

• CPUFREQD_MODULE=""
• CPUFREQD_MODULE_OPTS=""

22.4 My battery has much shorter lifetime than when I bought my laptop

As older a battery as worse its capacity. But it may still work suitable, only the values delivered to the OS may be wrong.

Try:

• If your BIOS does support refreshing (emptying) of your battery do it. Empty it totally and then be sure you fully charge it again. You should refresh your battery regularly (see manual of your laptop).
• Measuring battery values is more complex using ACPI. It could be that your battery shows the OS a remaining capacity of zero, but could still work for an hour or even longer (specially older batteries). Boot your system in APM mode (if supported) using the bootparam: acpi=off. This sometimes helps.

22.5 My battery shows totally weird values, therefore power management is going crazy

See section above.

22.6 My processor does not run with maximum CPU frequency

This is a feature, not a bug. The processor's frequency is lowered if supported and the processor is idle. Try:
cat /dev/zero > /dev/null &
or
glxgears

The system's load should then be on 100% and the processor should run at highest speed (see cat /proc/cpuinfo)

22.7 I cannot use the daemon related functions of the powersave binary

If you encounter following error using the powersave binary: Could not connect to daemon. Is the daemon running? Are you privileged to connect to the powersave daemon?

You probably have a DBus connection problem. Check the security config file for the powersave daemon in the DBus configuration (default: /etc/dbus-1/system.d/powersave.conf).

Try to restart the DBus daemon.

22.8 My system runs very slow

Do powersave -c. If POWERSAVE is returned your CPU always runs on lowest frequency.

A slow system could of course have totally other reasons. Check your system (top, ps, ...).

Have a look in /proc/acpi/processor/*/throttling. If the state is not T0 even your CPU load is high disable throttling in your scheme configuration files (see Schemes).

Another reason could be that you use the p4-clockmod module (verify by: lsmod |grep p4). You should not do that. Throttling is done through another interface. Using both slows down the CPU unpredictable. Be sure this module is not used in /etc/powersave/cpufreq or loaded in any other way.