Can the microphone jack be disabled?

Message

dgulotta · Post by **dgulotta** » Sat Jun 16, 2012 11:00 pm

I am having some problems with recording that I think may be caused by the sound card erroneously thinking that I have an external microphone plugged in. Am I correct in assuming that "Pin-ctls: 0x24 IN VREF_80" indicates that the system thinks that there is an external microphone plugged in? If so, is there a way I can tell ALSA to ignore the microphone jack?

Code: Select all

/proc/asound/card0/codec#0 snippet

Node 0x0b [Pin Complex] wcaps 0x400081: Stereo
  Control: name="Mic Jack Mode", index=0, device=0
    ControlAmp: chs=0, dir=In, idx=0, ofs=0
  Control: name="Mic Jack", index=0, device=0
  Pincap 0x00001724: IN Detect
    Vref caps: HIZ 50 GRD 80
  Pin Default 0x03a1102e: [Jack] Mic at Ext Left
    Conn = 1/8, Color = Black
    DefAssociation = 0x2, Sequence = 0xe
  Pin-ctls: 0x24: IN VREF_80
  Unsolicited: tag=03, enabled=1

whig · Post by **whig** » Sat Jun 16, 2012 11:18 pm

Have you looked in the mixer controls? Cards can have controls like 'Mic Boost'

dgulotta · Post by **dgulotta** » Sun Jun 17, 2012 2:22 am

I tried toggling the mixer controls, but no matter what I do, I just get static.

whig · Post by **whig** » Sun Jun 17, 2012 8:47 am

One last idea. Set off a recorder. Plug a music source into each line and microphone input in turn. How loud - or not - the recording is might reveal the noise sources and which input/s work best. The microphone can be the best.

pigiron · Post by **pigiron** » Mon Jun 18, 2012 4:58 pm

An Ubuntu developer created a Python-2 program that will display any current ALSA jack sense. You can get it here:

http://ppa.launchpad.net/diwic/ppa/ubun ... hda-tools/

It also includes many of the other ALSA HDA tools.

It's kind of goofy to get it set up. First you need to go into the hda-analyzer directory and use the patch command, feeding it the debian/patches/hda-jack-sense-test.patch file.

And that hda-analyzer program will allow you to change almost all of your codec connections.

Edited to add:

Here's an example output on my box:

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# ./hda-jack-sense-test.py -c0 -d2
Pin 0x14 (Green Line Out): present = Yes
Pin 0x18 (Pink Mic): present = No
Pin 0x19 (Pink Mic): present = No
Pin 0x1a (Blue Line In): present = No
Pin 0x1b (Green HP Out): present = No

dgulotta · Post by **dgulotta** » Thu Jun 21, 2012 1:12 am

Thanks. It appears that my system does in fact believe that there is an external microphone plugged in. Is there a way to tell ALSA that I want to use the builtin microphone anyway?