Power Issue

Description:

Despite having a 6 cell battery, the netbooks don't seem to be lasting as long on a single charge as you might expect.

As a comparison, on a 3 cell Asus EEE 1001HA (last years model), I get around 4-5 hours. On the Manaiakalani machines, I get around 6 hours.

Analysis:

Running powertop reveals that the laptops are using around 7.5-8.5W.

Powertop's suggestions:

• • Enable HD audio powersave mode by executing echo 1 > /sys/module/snd_hda_intel/parameters/power_save

    • Savings: approximately 0.5W

    • Risk Analysis:

      • Given the current sound issues, this may introduce something else to take into account.

    • Recommendation

      • Given that the microphone issue is unlikely to be fixed quickly, I suggest this is implemented ASAP.

  • Enable USB autosuspend for non-input devices

    • Savings: approximately 0.5W

    • Risk Analysis:

      • There is the risk of USB devices not working properly as well the work needed to implement this change being huge.

    • Recommendation:

      • Re-visit this issue at a later date.

  • Enable SATA ALPM link power management (echo min_power > /sys/class/scsi_host/host0/link_power_management_policy

    • Savings: approximately 0.8W

    • Risk Analysis:

      • No risks found

    • Recommendation:

      • Implement ASAP

Chosen Action

Immediate:

Implement HD audio powersave mode and SATA ALPM link power management in new build.

Add a page for making the battery last longer by:

• • Turning down screen brightness.

  • Possibly turning off wi-fi when it's not being used? (Though quite unlikely).

Long Term:

Re-visit to see what other tweaks can be accomplished.