9 /

Audio

If the sound card is detected:

; ls '#A'
'#A/audio'
'#A/audioctl'
'#A/audiostat'
'#A/volume'

; ls /dev/audiostat

You can check which pins are being used for input and output (output for Thinkpad x200):

; cat /dev/audiostat
bufsize   1024 buffered      0
codec 0 pin 25 inpin 29
aout 16 c1d
aout 17 c1d
aout 18 211
beep 19 70000c
ain 20 100d1b ← pin 29, pin 23
ain 21 100d1b ← pin 24
pin 22 out jack ext right hpout green ← aout 16, aout 17
pin 23 in nothing sep rear micin pink
pin 24 in jack ext right micin pink
pin 25 out nothing sep rear hpout green ← aout 16, aout 17
pin 26 out fix int N/A speaker ? eapd ← aout 16, aout 17
pin 27 out nothing ext N/A other ? eapd ← aout 16, aout 17
pin 28 out nothing ext N/A other ? ← aout 18
pin 29 in fix int N/A micin ?
beep 30 f00000
outpath aout 16 → pin 26
outamp aout 16
inpath pin 29 → ain 20
inamp ain 20

This line codec 0 pin 25 inpin 29 shows that pin 25 is being used for output and pin 29 used for input. On my laptop, it is necessary to set the output pin to 26:

; echo pin 26 > /dev/audioctl

Now it's possible to play music:

; audio/oggdec < music.ogg >/dev/audio
; audio/mp3dec < music.mp3 >/dev/audio

Sources: