Messages in this thread | | | Date | Sat, 22 Sep 2007 19:08:24 +0200 | From | Hans de Goede <> | Subject | Re: [linux-usb-devel] USB autosuspend and turning of usb pendrive leds |
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Alan Stern wrote: > On Sat, 22 Sep 2007, Hans de Goede wrote: > >> 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. > > I don't know what went wrong. It works fine on my systems. You did > fill in the correct device path for the "...", right?
Yes, the one that comes and goes as I plug in one of the USB-sticks I ue for testing.
> And you don't > need the "-n" -- adding it shouldn't matter, but you should try reading > back the contents of those files to make sure the values did get > written correctly. >
I did read them back and it did get written correctly.
>> 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?
If so I must say I find that a little counter intuitive.
Regards,
Hans
p.s.
As always, please keep me CC-ed, not on the list.
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