Module device mapping options

From the ALSA wiki

Latest revision as of 19:28, 6 January 2007

Systems can have two PCM and/or MIDI devices. Usually, the first PCM device (hw:0,0 in ALSA) is mapped to /dev/dsp0 and the secondary device (hw:0,1) to /dev/adsp0 (if available). For MIDI, /dev/midi0 and /dev/amidi0 for the first and second devices, respectively.

You can change this device mapping via the module options for snd-pcm-oss and snd-rawmidi

The following options are available for snd-pcm-oss:

• dsp_map -- the PCM device number assigned to /dev/dspX (default = 0)
• adsp_map -- PCM device number assigned to /dev/adspX (default = 1)

For example, to map the third PCM device (hw:0,2) to /dev/adsp0, do like this:

options snd-pcm-oss adsp_map=2

(need more here; where does the above line get put? somewhere in /etc/modutils.d?)

The options take arrays. For configuring the second card, specify two entries separated by comma. For example, to map the third PCM device on the second card to /dev/adsp1, define like below:

options snd-pcm-oss adsp_map=0,2

To change the mapping of MIDI devices, the following options are available for snd-rawmidi:

• midi_map -- MIDI device number assigned to /dev/midi0X (default = 0)
• amidi_map -- MIDI device number assigned to /dev/amidi0X (default = 1)

For example, to assign the third MIDI device on the first card to /dev/midi00, define as follows:

options snd-rawmidi midi_map=2