Power savings on USB Hard drives

[Nate Lawson]

Kevin Oberman wrote:
>> Date: Sun, 02 Dec 2007 16:15:05 -0800
>> From: Nate Lawson <nate at root.org>
>> Sender: owner-freebsd-acpi at freebsd.org
>>
>> Laurent LEVIER wrote:
>>> Hi Guys,
>>>
>>> I am using FreeBSD 6.2, soon 7.0 over a server and a laptop.
>>>
>>> I would like, on both configurations, to be able to have hard drive
>>> power savings as on internal IDE drives.
>>>
>>> At the moment, my external USB2 drive, when mounted but even not
>>> adresses, keeps running permanently despite it is just mounted for
>>> backups (no access out of backup times on sunday then).
>>>
>>> I digged on mailing lists, but cant find why the HD keep running.
>>>
>>> Can someone help?
>>>
>>> Thanks in advance
>>>
>>> Brgrds
>> This is outside the realm of acpi.  Have you tried the ataidle ported
>> application?  It works for most internal drives but I'm not sure how it
>> would do over USB.
> 
> Almost all external USB drives use umass and are not handled as ATA but
> as SCSI. As such, camcontrol is the tool that should probably be
> used, but I have no such devices and I don't know what the appropriate
> command might be.
> 
> Asking on usb@ might provide the needed information.

Hmm, camcontrol stop/start used to work for Fibre Channel drives back in
2001.  I have no idea what his usb interface might support though.

-- 
Nate