CMI_INTR_PER_BUFFER
i = sz / (ch->bps * CMI_INTR_PER_BUFFER) - 1;
if (blocksize > sc->bufsz / CMI_INTR_PER_BUFFER) {
blocksize = sc->bufsz / CMI_INTR_PER_BUFFER;
sndbuf_resize(ch->buffer, CMI_INTR_PER_BUFFER, blocksize);