HIDRAW_BUFFER_SIZE
next = (sc->sc_tail + 1) % HIDRAW_BUFFER_SIZE;
sc->sc_q = malloc(sc->sc_rdesc->rdsize * HIDRAW_BUFFER_SIZE, M_DEVBUF,
sc->sc_qlen = malloc(sizeof(hid_size_t) * HIDRAW_BUFFER_SIZE, M_DEVBUF,
sc->sc_head = (sc->sc_head + 1) % HIDRAW_BUFFER_SIZE;
sc->sc_rdesc->rdsize * HIDRAW_BUFFER_SIZE,