SEGS_PER_CHAN
#define NSEGS NCHANS * SEGS_PER_CHAN /* Segments in SGD table */
ch->sgd_addr = via->sgd_addr + sizeof(struct via_dma_op) * SEGS_PER_CHAN;
ch->sgd_table = &via->sgd_table[SEGS_PER_CHAN];
sndbuf_resize(ch->buffer, SEGS_PER_CHAN, ch->blksz);
seg = SEGS_PER_CHAN;
ptr = (seg * ch->buffer->bufsize / SEGS_PER_CHAN) - len;