Comment 3 for bug 31512

Are you seeing battery events at all in that log? Seems strange that they wouldn't appear.

You are right that it could be any process that's causing the writes, though specifically it has to be something that writes regularly with intervals greater than the hard disk park time. If several processes are writing to the disk then they are likely to interleave and keep the drive unparked constantly. On my Toshiba Libretto L5 and two ThinkPads I have access to it's been ACPID, and the existence of this bug led me to believe it's ACPID for others too.