CDCE_BULK_TX
usbd_xfer_set_stall(sc->sc_xfer[CDCE_BULK_TX]);
usbd_transfer_stop(sc->sc_xfer[CDCE_BULK_TX]);
[CDCE_BULK_TX] = {
[CDCE_BULK_TX] = {
usbd_transfer_start(sc->sc_xfer[CDCE_BULK_TX]);