mixer settings for voice recording?

H. Rosmanith moko at wildsau.enemy.org
Tue Jul 29 17:05:52 CEST 2008

Hello Andy,

> Somebody in the thread at some point said:
> | So, what is required to make the dsp-device delive audio-data?
> |
> | Q: The hardware does support this, right?
> Yeah.
> | Q: Is it a audio-driver problem, e.g. the alsa-device-driver for the chip
> |    doesnt support audio capturing?
> |
> | Q: Is it a problem with my mixer settings? If so, which are the correct
> |    mixer settings?
> I can't give you a straight answer on what to do, but here is the
> situation around it.
> The normal audio routing for the microphone inside the WM8753 codec is
> to bring it in on "MIC2" port and then send it via an "analogue path"
> around some scalers and mixers and switches and send it back out again
> on MONO1 / MONO2 to the GSM chip. 
> In short it doesn't get delivered to the ADC in the Wolfson where you can pull it as normal PCM.

okay, this means "normally the wm8753 is not configured to do this, but
you can configure it to make it work", right?

and if configured correctly, which is:
> If the PGA and mux are configured, it should work OK.

then /dev/dsp will output PCM data?

> One last consideration, the Mic is OFF unless you enabled MICBIAS signal
> to power it.

hm ... I dunno how to do this. In alsamixer, in the capture view, I see
several controls, like e.g. PCM, Mic1, Mic2, Capture. I've put them all
to 100% and unmuted them. Still there's no activity on /dev/dsp.
On the other hand, I don't see a "MICBIAS" control.

If it helps, I could copy the contents of /etc/asound.state into an email.

kind regards,
H. Rosmanith

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