Re: [gentoo-user] Anyone get Acer laptop internal microphone working in Gentoo?

[YoYo Siska <yoyo@gl.ksp.sk>]

On Sun, Feb 20, 2011 at 08:33:22PM -0500, Walter Dnes wrote:
> On Sun, Feb 20, 2011 at 12:09:27PM +0000, Mick wrote
> > Indeed, the Gentoo Alsa Guide still says pretty much the same thing:
> > 
> > "Please note that for ease of use, all examples show ALSA built as
> > modules. It is advisable to follow the same as it then allows the
> > use of alsaconf which is a boon when you want to configure your card."
> > 
> > I've added some options for my alsa modules in
> > /etc/modprobe.d/alsa-base.conf, e.g.:
> > 
> >   options snd-hda-intel enable_msi=1
> 
>   This is exasperating.  After re-building alsa sound support as kernel
> modules, rather than built into the kernel, I see some improvement.
> When I blow into the internal mic I hear it from the laptop speakers.
> With mic-boost turned up, I can hear myself echoing when I talk into the
> internal mic or into an external mic.  Turn up the boost high enough,
> and the external mic generates a mean high-ptched feedback squeal,
> unless I also plug in headphones.
> 
>   So the hardware is working now, *BUT I STILL CAN'T RECORD THE BLEEPING
> THING*.  When I try "ffmpeg -f oss -i /dev/dsp audio.wav" it thinks it's
> recording, but the output file is only hiss.   Ditto for the command
> "ffmpeg -f alsa -i plughw:0,0 audio.wav".

Seems that the mic works, but is not selected for capture... (routing it
to speakers recording from it are two different things ;)

You basically need to tell alsa which sources to record from, which may
be different from which are just unmuted in the mixer (and thus playing
from the speakers). I've seen a few different sets of alsa controls on
different sound cards that control the record sources, these are the two I remember:

Run alsamixer, pres F4 (capture) and either look for
- a "mic" control (along with CD, Line, Aux,... controls), then make sure it has a red "CAPTURE" text (spacebar
  toggles CAPTURE)
- if you dont't have separate Mic, Line, ... controls, try looking for a
  "Input source" control, you should be able to use up/down arrows to
  change it to mic

Also in both cases make sure a "Capture" control has CAPTURE on too..
You might have more Mic sources two choose from, or you might also have
a "Mic Select" control, with which you can switch between different
mics, so you might have to experiment to find which is the correct
one...

yoyo