wsmux_do_ioctl
static int wsmux_do_ioctl(device_t, u_long, void *,int,struct lwp *);
wsmux_mux_open, wsmux_mux_close, wsmux_do_ioctl, wsmux_do_displayioctl,
return wsmux_do_ioctl(wsmuxdevs[u]->sc_base.me_dv, cmd, data, flag, l);