Date: Sat, 22 Sep 2007 16:12:16 -0400 (EDT)
From: Alan Stern <stern@rowland.harvard.edu>
To: Hans de Goede <j.w.r.degoede@hhs.nl>
cc: linux-kernel <linux-kernel@vger.kernel.org>,
       USB development list <linux-usb-devel@lists.sourceforge.net>
Subject: Re: [linux-usb-devel] USB autosuspend and turning of usb pendrive
 leds
In-Reply-To: <46F54C08.3050300@hhs.nl>
Message-ID: <Pine.LNX.4.44L0.0709221610170.31951-100000@netrider.rowland.org>
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On Sat, 22 Sep 2007, Hans de Goede wrote:

> >> Now call me naive, but I would expect a mass-storage devices with no 
> >> partitions mounted to autosuspend when autosuspend is enabled for that device.
> > 
> > Yes, that is naive.  The driver has no way to tell whether or not any 
> > partitions are mounted.  Furthermore, you might very well want to 
> > access the raw device without mounting any partitions (database 
> > managers frequently do such things to reduce I/O overhead), in which 
> > case you certainly would not the device to be autosuspended.
> > 
> 
> How does this relate to your "It works fine on my systems" remark, do I need to 
> do anything other the unmounting the paritions to make the device eligible for 
> autosuspend, like unbind the sd driver or even the usb-storage driver?

You shouldn't have to do anything.  Mounted or unmounted, bound to sd
or not bound, it shouldn't matter.  Provided the device isn't being
used, it ought to autosuspend.

I repeat: To find out what is really happening, you should use usbmon.

Alan Stern

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