SEQ_MAXQ
sc->pcq = pcq_create(SEQ_MAXQ, KM_SLEEP);
sc->lowat = SEQ_MAXQ / 2;
t = SEQ_MAXQ - *(int *)addr / sizeof (seq_event_rec);
if (t > SEQ_MAXQ)
t = SEQ_MAXQ;
seq_event_t buf[SEQ_MAXQ];
#define SEQ_QFULL(q) ((q)->count >= SEQ_MAXQ)
#define SEQ_QPUT(q, e) ((q)->buf[(q)->in++] = (e), (q)->in %= SEQ_MAXQ, (q)->count++)
#define SEQ_QGET(q, e) ((e) = (q)->buf[(q)->out++], (q)->out %= SEQ_MAXQ, (q)->count--)