REP_DELAYN
callout_schedule(&sc->sc_rawrepeat_ch, hz * REP_DELAYN / 1000);
callout_schedule(&sc->sc_roll_to, hz * REP_DELAYN / 1000 / 2);
callout_schedule(&sc->sc_repeat, hz * REP_DELAYN / 1000);
callout_reset(&sc->sc_rawrepeat_ch, hz * REP_DELAYN / 1000,