Linux Exaudio Driver

Here you find Linux drivers for Creative's Extigy USB sound card. This was made from the generic OSS "audio" USB driver, but I hacked it to offer working mixer controls. I also added new code to support AC3 sound and the IR remote. The package includes two separate modules:

• exaudio provides audio playback and recording
• exaudio_remote provides IR remote functionality

Instructions and Downloads by Kernel Version

• Linux Kernel 2.4.x
• Linux Kernel 2.6.x

Driver Status

• Exaudio SF.net project page

• Browse the CVS pages

• Firmware version: The current driver works with firmware version 1.1.020507 which can downloaded from Creative's web site. You can only upgrade the firmware under windoze, I'm afraid. I have tried to keep an option to support the origial firmware that came with the device (I got mine in January 2002). To enable this option, add ORIG_FIRMWARE=1 to the make command line.

• Audio play/recording: This seems to work fine and has not been changed from the original audio driver. The device will record stereo at 48, 32, 24, 16, or 8 KHz. The device only plays at 48 KHz. (It appears that the 44.1 and 22.05 KHz modes are only for CMSS mode). So, to play 44.1 KHz audio files, the player program must be able to do rate conversion (sox can do this, and so can xmms).

• AC3 surround sound: The third dsp device will accept an AC3 stream formatted for SPDIF, like xine provides. In your '.xine/config' you need to force xine to use the third dsp device and to enable AC3 pass through. For example, using xine version v0.99.3, to use /dev/dsp3, put:

  # audio driver to use
  # { auto  null  alsa  oss  esd  file  none }, default: 0
  audio.driver:oss
  
  # OSS audio device name
  # { auto  /dev/dsp  /dev/sound/dsp }, default: 0
  audio.device.oss_device_name:/dev/dsp
  
  # OSS audio device number, -1 for none
  # numeric, default: -1
  audio.device.oss_device_number:3
  
  # speaker arrangement
  # { Mono 1.0  Stereo 2.0  Headphones 2.0  Stereo 2.1  Surround 3.0  Surround 4.0  Surround 4.1  Surround 5.0  Surround 5.1  Surround 6.0  Surround 6.1  Surround 7.1  Pass Through }, default: 1
  audio.output.speaker_arrangement:Pass Through
  
  

  The extigy has eight speaker modes when decoding AC3 audio:

             L
             F
  mode Rs Ls E  C  R  L
  ---------------------
  1    0  0  0  0  1  1
  2    0  0  0  0  1  1
  3    0  0  1  0  1  1
  4    1  1  0  0  1  1
  5    1  1  1  0  1  1
  6    1  1  0  1  1  1
  7    1  1  1  1  1  1
  8  -- pass through -- 
  
    Channel names: 
    Rs = Right surround, Ls = Left surround, 
    LFE = Low frequency enhancement, C = Center front, 
    R = Right front, L = Left front 
  

  You can use the utility program, ac3mode, for setting the mode. Do 'ac3mode -h' for help on this program.

• CMSS surround sound and multichannel PCM: For PCM audio, only the front speakers and the headphones work. The driver makes the CMSS LED turn on, but this is purely for entertainment only! The CMSS function will probably never work, since when playing more than two channels the device appears to use some sort of (proprietary) ADPCM.

• Front panel knobs and buttons: The volume knob and the CMSS button have the same effect as pressing the corresponding buttons on the IR remote. See below to find out how to enable IR events. The microphone gain knob is an analog control.

• Mixer controls: The driver implements each "feature unit" as a separate mixer control. The driver creates two mixer controls, one for recording and one for playback. The playback mixer has many controls, most of which seem to have the same effect. Here is a block diagram of the internal controls that are advertised by the USB descriptors from the card.

• MIDI: MIDI works with this device, but the exaudio driver itself does not handle MIDI. You can use the usb-midi driver to send MIDI messages out to an external device via the raw MIDI device (like '/dev/midi00'). Reading MIDI in from the device does not work yet.

• Infrared Remote: The driver creates a new character device called '/dev/ir'. This device will receive a dynamic major number from the kernel, so you will need to create the device node yourself. The latest driver sources include a script, load.sh, to load the drivers and create the device node. You can run this script, or you can create the drive node by hand like this:
  1. Compile the driver.
  2. Load the module.
  3. Find the major device number by typing 'cat /proc/devices'. Look for the device called "ir", and note its number (it will probably be 254 or 253).
  4. As root, create a character device called '/dev/ir' with that major number, using the 'mknod' program.

  You can read the current IR button code as an integer from /dev/ir. The sources include three simple programs that read events from the remote:

  1. irkey is an example of how to read from /dev/ir. To compile it, type 'make irkey'.
  2. irxmms controls xmms. To compile it, type 'make -f Makfile.xmms'.
  3. irxine controls xine. To compile it, type 'make -f Makfile.xine'.

• LIRC Support: You can optionally include LIRC support by adding 'USE_LIRC=1' to your make command line. This will add LIRC plugin code to the driver. This code was developed using LIRC version 0.6.6.

  Here is a lircd.conf that works with the exaudio_remote driver.

Common Issues

Most of the problems reported are of the "getting a second sound card working" sort, as opposed to the driver gurgling the sound or crashing. If you cannot get the driver working, check the following items:

1. This might not work with the ohci driver (please send me a report if you try this). For 2.4.x kernels, use usb-uhci.o instead of uhci.o. It seems to work better.
2. Your kernel needs Open Sound System support (CONFIG_SOUND_OSS). If you have this as a module (sound.o), then load this module before you load exaudio.
3. You do not need generic USB audio support (called "audio", yes, a misleading name). If you need this for some other USB sound card, compile it as a module and load it after exaudio. If you load audio before exaudio, it claims the extigy's interfaces, mucking things up.
4. The exaudio driver uses three dsp devices and two mixer devices. If you do not have enough device nodes, then you must create them (as root) with the 'mknod' command (see 'man mknod' for how to do this). Here is a listing from a machine with four of each:

   $ ls -l /dev/dsp* /dev/mixer*
   crw-rw----    1 root     audio     14,   3 Mar 14  2002 /dev/dsp
   crw-rw----    1 root     audio     14,  19 Mar 14  2002 /dev/dsp1
   crw-rw----    1 root     audio     14,  35 Mar 14  2002 /dev/dsp2
   crw-rw----    1 root     audio     14,  51 Mar 14  2002 /dev/dsp3
   crw-rw----    1 root     audio     14,   0 Mar 14  2002 /dev/mixer
   crw-rw----    1 root     audio     14,  16 Mar 14  2002 /dev/mixer1
   crw-rw----    1 root     audio     14,  32 Mar 14  2002 /dev/mixer2
   crw-rw----    1 root     audio     14,  48 Mar 14  2002 /dev/mixer3
   

5. I do not use ALSA drivers or programs, and so I cannot say whether the exaudio driver works along side other ALSA drivers or not. Some SF users have reported success using ALSA drivers with the extigy. Check the Help Forum and the ALSA web site to learn about ALSA.

6. If all else fails...

• uname -a
• gcc --version (the gcc that you used to compile the driver)
• /sbin/lsmod
• ls -l /dev/dsp* /dev/mixer*
• grep exaudio /var/log/* (this one you must do as root)