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    SubjectRe: [REPOST PATCH 3/3] USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled
    On Wed, 8 Jul 2015, Julius Werner wrote:

    > > But I don't see how you will make it work when the root hub itself is
    > > not enabled for wakeup and a non-hub device plugged into one of the
    > > root hub's ports is enabled.
    > >
    > > It seems like you would need a usb_hcd_wakeup_not_needed(hcd, port)
    > > subroutine.
    >
    > We'd just put that in the Tegra platform driver, I guess. Iterate over
    > all ports, call usb_wakeup_enabled_descendants() on the connected
    > device (if any) and disable that port's PHY if it returns 0 or wasn't
    > connected. Since usb_wakeup_enabled_descendants() also counts
    > do_remote_wakeup from the device itself and is safe to call even on
    > non-hubs, that should work for all cases.

    All right, that seems reasonable. But remember not to do this if
    wakeup is enabled on the root hub -- in that case all the PHYs must
    remain powered because unplugging and plugging are both wakeup events.

    Alan Stern



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