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