KBADDKBD
kbd_ioctl(mux, KBADDKBD, (caddr_t) &ki);
kbd_ioctl(mux, KBADDKBD, (caddr_t) &ki);
case KBADDKBD: /* add keyboard to the mux */
case KBADDKBD: /* add/remove keyboard to/from mux */
kbd_ioctl(k0, KBADDKBD, (caddr_t) &ki);
mux_keyboard((opt == 'A')? KBRELKBD : KBADDKBD, optarg);