linux-kernel - Re: [linux-usb-devel] USB autosuspend and turning of usb pendrive leds

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Message-ID: <46F52012.5050902@hhs.nl>
Date:	Sat, 22 Sep 2007 16:00:50 +0200
From:	Hans de Goede <j.w.r.degoede@....nl>
To:	Alan Stern <stern@...land.harvard.edu>
CC:	linux-kernel <linux-kernel@...r.kernel.org>,
	USB development list <linux-usb-devel@...ts.sourceforge.net>
Subject: Re: [linux-usb-devel] USB autosuspend and turning of usb pendrive
 leds

Alan Stern wrote:
> The correct answer is that HAL should top polling while the device is 
> suspended.
> 
> In kernels starting with 2.6.23-rc6, the correct way to enable 
> autosuspend for a USB device is basically like this:
> 
> 	echo D >/sys/bus/usb/devices/.../power/autosuspend
> 	echo auto >/sys/bus/usb/devices/.../power/level
> 

I'm afraid that that doesn't work for usb mass-storage devices.

Here is what I did:
1) kill hal
2) insert usb stick -> led lights
3):
echo -n 1 >    /sys/bus/usb/devices/.../power/autosuspend
echo -n auto > /sys/bus/usb/devices/.../power/level

4) wait

Nothing happens, where as sending "suspend" to power/level does turn the led 
off. 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.

And yes I'm pretty sure nothing else is talking to the device.

As usual keep please me CC-ed as I'm not on the list.

Regards,

Hans
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