ADA_FLAG_CAN_RAHEAD
if (ADA_RA >= 0 && softc->flags & ADA_FLAG_CAN_RAHEAD)
softc->flags |= ADA_FLAG_CAN_RAHEAD;
softc->flags &= ~ADA_FLAG_CAN_RAHEAD;
if (ADA_RA >= 0 && softc->flags & ADA_FLAG_CAN_RAHEAD) {