UAUDIO_NCHANBUFS
usbd_transfer_unsetup(sc->sc_play_chan[i].xfer, UAUDIO_NCHANBUFS + 1);
usbd_transfer_unsetup(sc->sc_rec_chan[i].xfer, UAUDIO_NCHANBUFS + 1);
usbd_transfer_unsetup(chan->xfer, UAUDIO_NCHANBUFS + 1);
usbd_transfer_unsetup(chan->xfer, UAUDIO_NCHANBUFS + 1);
chan_alt->usb_cfg, UAUDIO_NCHANBUFS + 1, chan, &chan->lock)) {
#if (UAUDIO_NCHANBUFS != 2)
usbd_transfer_unsetup(chan->xfer, UAUDIO_NCHANBUFS + 1);
struct usb_xfer *xfer[UAUDIO_NCHANBUFS + 1];
usbd_transfer_start(ch->xfer[UAUDIO_NCHANBUFS]);
usbd_transfer_unsetup(ch->xfer, UAUDIO_NCHANBUFS + 1);
uaudio_cfg_record[UAUDIO_NCHANBUFS + 1] = {
uaudio_cfg_play[UAUDIO_NCHANBUFS + 1] = {