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    SubjectRe: [PATCH] PNPACPI: Enable Power Support
    Date
    Am Mittwoch, 10. Dezember 2008 10:53:15 schrieb Henrique de Moraes Holschuh:
    > Although I do wonder WTF we don't do that on our USB UHCI/EHCI kernel
    > drivers, that ACPI needs to step in to fix it.  If it is not a wake

    EHCI/UHCI have no way to power down host controllers.
    It needs external means, namely ACPI.

    > device, why are we leaving it powered up?  It is bad enough we don't
    > have any sort of proper USB power control, but to leave the entire USB
    > subsystem powered up without reason?!

    We don't. If you unplug all devices, USB will power down as much as is
    compatible with detecting new devices.

    > Vista not only powers down the USB HCIs and ports on STR, it also
    > powers down ports when you "safely remove the USB device", and seems
    > to leave the port powered down until you insert a device (or remove
    > the device already in there, whatever).

    If you cut power to a port, you cannot detect a hotplugging. You can
    suspend it, which Linux does do.

    Regards
    Oliver



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