Battery Life of a HP 5103

After reading the following articles, I decided to tweak battery life on my HP 5103. Before I started, I installed the latest Linux 3.1 kernel.

The battery usage without any tweaks was 11.4W as reported by powertop. I tested the option pcie_aspm=force and the power usage went down to 10.3W. Another tweak I did was to mount the / with the option noatime to reduce disk IO. If this option is set, reading accesses won’t be written (atime) to disk. However, I did not do any measurements.

Furthermore, I disabled bluetooth and added the following lines to rc.local (found here and here)

for i in /sys/class/scsi_host/host?/link_power_management_policy; do
    echo min_power > $i
done
for i in /sys/bus/usb/devices/*/power/autosuspend; do
    echo 1 > $i
done
for i in $(find /sys/devices/pci* -wholename "/sys/devices/pci*/power/control"); 
    do if [[ "$(cat $i)" == "on" ]]; then 
         echo "auto" > $i; 
    fi; 
done;

And now I’m down to 9.5W. Further reduction can be achieved by dimming the backligth.

If you want to have this done automatically, you may want to install laptop-mode-tools. However, you need first to change the line

Look for :
	"2.6" ) ;;

And add right after on line following, which ought to allow kernel 3.0, 3.12 .. 3.9876.

3.[0-9]*) ;;

If your mouse is only working after replugging, add it to the blacklist (in /etc/laptop-mode/conf.d/usb-autosuspend.conf set AUTOSUSPEND_USBID_BLACKLIST="046d:c018"), or buy a mouse that supports autosuspend. I also had to disable the WLAN autosuspend (/etc/laptop-mode/conf.d/wireless-power.conf), as this is with brcmsmac not possible.