usb_needs_explore
usb_needs_explore(sc->sc_hub, 0);
usb_needs_explore(sc->sc_bus->root_hub, 1);
usb_needs_explore(sc->sc_bus->root_hub, 0);
usb_needs_explore(dev, 0);
usb_needs_explore(sc->sc_bus->root_hub, 0);
void usb_needs_explore(struct usbd_device *, int);