Hi,
I also use this Intel ICH4 on thinkpad R50e,
I'm not sure about the reason why these 4 pcm interface is prepared by Alsa.
I use plughw:0,0 for playback.
plughw:0,0 and :0,3 for capture, so we can use 0 & 3 as duplex.
alsa shows below.
$cat /proc/asound/pcm
00-00: Intel ICH : Intel 82801DB-I
In my case,
alsamixer shows Intel 82801DB-ICH4 uses Analog Devices AD1981B as AC'97 Codec.
Chip spec may serve as a reference.
http://www.analog.com/en/prod/0,2877,AD1981B,00.html
It uses two ADC circits , which can be shown as ADC and ADC2 in the
'/proc/asound/pcm'
And have one SPDIF port.
What
