[alsa-devel] About Alsa arecord

Raymond Yau superquad.vortex2 at gmail.com
Tue Jan 8 03:27:57 CET 2013

> Good morning!
>                  Are you saying I should modify the source code of
>> > Hello!
>> >        There have 2 stereo ADCs support one stereo microphone and one
legacy mixer recording simultaneously, said in the document of ALC888
Datasheet .I inputed 1KHz sine wave into every pins
(Line1-R,Line1-L,MIC1-R,MIC1_L,MIC2-R,MIC2-L,LINE2-R,LINE2-L) of ALC888 by
signal genrator,and used command 'arecord -c 4 -f S16_LE -r 44100
>test.wav' recording in fedora14.but ALL audio data are recorded in channel
1,2.No any data in channel 3,4.Why?How can I record every pins audio data
in each channel?
>> In alc_auto_create_input_ctls , add the connection from node 0x0b of
mixer ADC as input source similar to those pin complex
>> Those Mic/line/CD playback volume and switches of node 0x0b affect the
signal of the new input source ”mixer”

Yes,  also need a switch which mute the input from 0x0b for all output
jacks to prevent feedback if using mic

the current hda driver only support stereo capture and you have to
implement multi channel capturing similar to multi channel playback in


     for (i = 1; i < num_adcs; i++) {
                      snd_hda_codec_setup_stream(codec, adc_nids[i],
stream_tag,  i * 2, format);


try multi plugin of two stereo capture devices

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