Developer Resources
PDF Documents
Caution: This version of this document is no longer maintained. For the latest documentation, see


Start an audio driver

Note: You must be root to start this manager.


io-audio [-d driver [driver_options]] [-o opt[,opt[,opt]]]

Runs on:



-d driver [driver_options]
Load the specified driver and pass it the given driver_options. For information on the drivers and their syntax and options, see the deva-* entries:
Driver: Shared object:
-o global_options
Global options. The global_options variable can be any of the following:
  • config_write_delay=time

    The time in seconds after the last change before soundcard settings are written to disk, (a value of -1 prevents the settings from ever being written).

  • max_dma_buf_size=size

    The maximum size, in kilobytes, for the DMA buffer.

  • disable_sw_mixer

    On cards that have only a single channel in hardware, do not use software techniques to increase the maximum number of playing channels.

Note: See the list of shared objects (below) for details about local options for specific drivers.

Increase the level of verbose output.


The io-audio manager provides support for dynamically loaded audio-driver modules. This utility enables you to load the audio drivers specified by the -d options when you start io-audio.

Note: You can start more than one driver by using multiple -d command-line options, but don't try to start more than one instance of io-audio.

Once io-audio has started, you can dynamically load and unload drivers using the mount and umount commands. E.g. this command:

io-audio -dvortex -daudiopci &

gives the same result as this sequence:

io-audio &
mount -T io-audio vortex
mount -T io-audio audiopci

Note: When searching for shared objects, the io-audio manager uses the LD_LIBRARY_PATH environment variable.

To unload a module, use a command like this:

umount /dev/snd/controlC0


Provide support for Aureal Vortex sound card:

io-audio -vv -d vortex &


The io-audio command can load the following shared objects:
Sound driver for the Trident 4DWave!.
Sound driver for the AudioPCI chip family.
Sound driver for the CS4281.
Sound driver for the CS46xx family of chips.
Sound driver for the ESS1938.
Sound driver for the National Semiconductor Geode family of chips.
Sound driver for the Intel 8X0.
Sound driver for the Neomagic 6 family of chips.
Sound driver for the VIA686.
Sound driver for the Vortex.
Sound driver for the Yamaha DS1.
Mixer DLL for the AC97 codec.
Mixer DLL for the AK4531 codec.
Shared object used to restore an audio driver's state.

See also:

Connecting Hardware in the Neutrino User's Guide