Comment 690 for bug 59695

Ciso,

On battery the default value is still hdparm -B 128, which does allow the drive to park the heads. This upload only changes the default policy when running on AC.

For some drives, it's possible that the -B 128 battery policy is different than the firmware default and as a result the drive has a longer idle time between parking; this will not be true /generally/, and is a largely harmless side effect of the change rather than a deliberate bugfix.