Hi,

I am using AT91SAM9263 controller and linux2.6.20-4 for development. I need to develop voice communication within the intranet between these embedded devices.

I am able to “cat abcd.au > /dev audio” and play the audio file on the speaker, after unmuting the register in the file sound/arm/at91-ac97.c.

But when I do cat /dev/audio > /tmp/123 it says

#cat /dev/audio > /tmp123
cat /dev/audio : Invalid argument.

I am not sure why this problem is occurring. I put lots of printk messages in the file sound/arm/at91-ac97.c.

I have enabled debug messages in the kernel and don’t see any debug messages also.

I am not sure why this is happening.

Hoping positive reply from you.


With regards

Shashi Kumar. M.S.

Software Engineer,
Aspire Communications (P) Limited
Plot 64-C1, Hootagalli Industrial Area
Kasaba Hobli, Mysore 570 018
Ph: +91-821-4288772/3
Fax ;+91-821-4287774
Cell: +91-99001-46678
URL: www.aspirecommunication.com

Dear Sir,

Thanks for reading.

Can i know the register used to unmute the sound in at91-ac97 file available in /sound/arm/

Failed to hear sound from a headphone when an audio file is played using this command..
cat xyz.au >/dev/audio

Eventhough i enabled all debug options in kernel configuration, but dont see any error messages on console when my audio file is played.

Please acknowledge.

Regards,

Hi,
Hope you are using 2.6.20-11 linux kernel provided by timesys.

I did the following changes to un mute the speaker. you can do these things with the ALSA utils using the ALSA control (alsactl).

Add the following code in the file sound/pci/ac97/ac97_codec.c and in the function snd_ac97_mixer before returning from this function.

snd_ac97_write(ac97, AC97_MASTER, 0x0707);
snd_ac97_write(ac97, AC97_HEADPHONE, 0x0707);
snd_ac97_write(ac97, AC97_MASTER_MONO, 0x0007);
snd_ac97_write(ac97, AC97_PHONE, 0x0007);
snd_ac97_write(ac97, AC97_MIC, 0x0007);
snd_ac97_write(ac97, AC97_LINE, 0x0707);
snd_ac97_write(ac97, AC97_PCM, 0x0707);

these line of code will unmute the things. may be all things are not required. but atleast first two lines and the last lines are mandatory as PCM_OUT has to be muted.

with regards
Shashi