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    SubjectRe: Enable CONFIG_USB_SUSPEND by default or some mobile HD can't be unplugged safely
    On Thu, 1 Jan 2009, Alexander E. Patrakov wrote:

    > Yan Li wrote:
    > > Hello List,
    > >
    > > By default CONFIG_USB_SUSPEND is not enabled and today I got bite by
    > > this when I got a new WDC My Book hard drive. I have no way to unplug
    > > it safely, according to it's manual, with a kernel that doesn't have
    > >
    > > On it's manual read "you should unplug and remove the device only when
    > > the light is off." On Linux unmounting it won't turn it's light off
    > > and I can feel it's motor is still running. The only way to unplug it
    > > properly on a Linux system, as to my knowledge, is to echo `suspend'
    > > to `/sys/bus/usb/devices/$DEV/power/level'. And one has to have
    > > CONFIG_USB_SUSPEND=y to do this.
    > >
    > > On Windows and Mac OS, `safely remove this device' function effectly
    > > turns it into `suspend' mode, and it's light off.
    > You have obviously tested only Windows XP, because Vista doesn't cut the
    > power for at least some USB devices.

    Yan never said that Windows cuts any power; he only said that the light
    turns off. This is accomplished by disabling the USB port, not by
    cutting power.

    > And congratulations for obtaining a
    > Vista-incompatible hard drive (of course, joking).
    > BTW, does the "eject /dev/$DEV" command help?

    I wouldn't expect it to help, since it doesn't disable the port or put
    the device into suspend mode.

    Alan Stern

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