Over 9 Hours of Video on Battery with the MSI Wind U110

After I've managed to set up the video acceleration, it was time to test if it's really as power efficient as claimed. I just tried that with some SD and HD video. HD video wouldn't play properly of course, so it's silly to compare battery times.

But with SD video and vaapi, I managed to get down to 6.1 watts (9.1 hours). Without vaapi it was around 6.3-6.5 watts (8.5 hours).

I used a few tricks to achieve this:
  1. disabled wifi and bluetooth.
  2. lowered the display brightness to minum (still good though). This has to be done before boot in 2.6.31.
  3. moved the system to an SDHC card. While the power in standby is the same (5.7 watts both with only SDHC or only hard disk), the active power is much lower with the SDHC (only +0.5-2 watts instead of 3-5 watts).
  4. used by powersave script to optimize the kernel settings for low power mode:
echo cpu
echo 1 | tee /sys/devices/system/cpu/sched_smt_power_savings
echo 1 | tee /sys/devices/system/cpu/cpu*/cpufreq/ondemand/ignore_nice_load
echo 95 | tee /sys/devices/system/cpu/cpu*/cpufreq/ondemand/up_threshold
echo 50 | tee /sys/devices/system/cpu/cpu0/cpufreq/ondemand/powersave_bias

echo usb
echo 2 | tee /sys/module/usbcore/parameters/autosuspend
echo auto | tee /sys/bus/usb/devices/*/power/level

echo misc
echo 1500 | tee /proc/sys/vm/dirty_writeback_centisecs
echo 0 | tee /sys/block/sdb/queue/rotational
# broken echo 10 | tee /sys/module/snd_hda_intel/parameters/power_save
# not better echo 1 | tee /sys/module/psb/parameters/disable_vsync

killall -q hald-addon-storage knotify4 NetworkManager
hciconfig hci0 down

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