RX_BUFFER_SIZE
sc->sc_rxbuffer[0] = kmem_alloc(RX_BUFFER_SIZE, KM_SLEEP);
sc->sc_rxbuffer[1] = kmem_alloc(RX_BUFFER_SIZE, KM_SLEEP);
kmem_free(sc->sc_rxbuffer[0], RX_BUFFER_SIZE);
kmem_free(sc->sc_rxbuffer[1], RX_BUFFER_SIZE);
if (sc->sc_rxpos < RX_BUFFER_SIZE) {