S_RING_BLANK
if (ringp->s_ring_state & S_RING_BLANK ||
(ringp->s_ring_state & S_RING_BLANK)) {
!(ringp->s_ring_state & S_RING_BLANK) &&
(ringp->s_ring_state & (S_RING_BLOCK|S_RING_BLANK))) &&
ringp->s_ring_state &= ~S_RING_BLANK;
ringp->s_ring_state |= S_RING_BLANK;