SNDRV_CHMAP_UNKNOWN 317 sound/usb/stream.c chmap->map[c] = SNDRV_CHMAP_UNKNOWN; SNDRV_CHMAP_UNKNOWN 450 sound/usb/stream.c map = SNDRV_CHMAP_UNKNOWN; SNDRV_CHMAP_UNKNOWN 464 sound/usb/stream.c chmap->map[c] = SNDRV_CHMAP_UNKNOWN;