[alsa-devel] Thinkpad T400 - internal mic doesn't work, can't set CAPTURE - schematics included

David Henningsson david.henningsson at canonical.com
Thu Feb 28 10:28:16 CET 2013

On 02/27/2013 06:58 PM, Arkadiusz Miśkiewicz wrote:
> Hi,
> My Thinkpad T400 (2764CTO model) doesn't have ability to set CAPTURE on
> microphone inputs with alsa. Most likely some quirk is missing.
> The laptop has internal microphone, microphone in input, headphones out output
> and 2 internal speakers. That's all.
> Is uses Conexant CX20561_15Z internally and there is detailed T400 schematic
> available:
> http://kythuatphancung.com/download/lenovo-thinkpad-t400-schematic-
> diagram.html?dl
> (for audio look around page 43).
> Kernels 3.7.x, fresh 3.8 - no luck. Tried even linux-next from today but it
> dies early on alsa unrelated issues.
> I've tried model options laptop, hp, hp-dv6736, hp-700, toshiba, ideapad,
> auto. None of these work fine. With model=hp-700 I can set CAPTURE but it
> doesn't work (silent audio is captured using arecord or in google hangout).
> External mic connected also doesn't work with these setups.
> http://www.alsa-project.org/db/?f=394ff4cdca33e75c8a47203d42b89d8de36deca7
> [3.8 kernel]
> http://www.alsa-project.org/db/?f=302877e50f99835075d038207f6db0dfd89873b0
> [3.7 kernel]
> Thinkpad is 2764CTO model exactly.
> I can test various hacks, patches etc easily. Could someone look at schematic
> and provide quirks to test?


What do you mean with "doesn't have ability to set CAPTURE"? What input 
is used is automatically selected depending on what you have plugged in, 
and its level is set using mixer controls (which in your alsa-info is 
set to minimum levels).

David Henningsson, Canonical Ltd.

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