DCONS_CON
cp->cn_arg = (void *)&sc[DCONS_CON]; /* share port0 with unit0 */
dcons_attach_port(DCONS_CON, "dcons", 0);
dcons_detach(DCONS_CON);
p = &sc.port[DCONS_CON];
#define IS_CONSOLE(p) ((p)->port == DCONS_CON)