[alsa-devel] M-Audio Audiophile USB, native little endian (S16_LE) ?

Hakan Lennestal Hakan.Lennestal at brfsodrahamn.se
Sun Jul 8 15:36:18 CEST 2007

Hi all !

I don't know if this is already known (?), but the M-Audio Audiophile USB
seem to be possible to run in native S16_LE mode if initialized with
device_setup=0x01 (possibly with 0x11 also, have not tested that).

This is at least the case with my rather new box (bought a couple of 
weeks ago).

Patch for usb/usbaudio.c (alsa-driver-1.0.14):

  static int is_big_endian_format(struct snd_usb_audio *chip, struct 
audioformat *fp)
        switch (chip->usb_id) {
        case USB_ID(0x0763, 0x2001): /* M-Audio Quattro: captured data only */
                if (fp->endpoint & USB_DIR_IN)
                        return 1;
        case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
  +             // Is small endian if setup with 0x01 !
  +             if (device_setup[chip->index] != 0x01)
                   return 1;
        return 0;


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