SV_INTR_PER_BUFFER
RANGE(blocksize, SV_MIN_BLKSZ, sc->bufsz / SV_INTR_PER_BUFFER);
sndbuf_resize(ch->buffer, SV_INTR_PER_BUFFER, blocksize);
count = count / SV_INTR_PER_BUFFER - 1;
count = count / SV_INTR_PER_BUFFER - 1;