[alsa-devel] Conexant CX20582 HDA codec support

[Takashi Iwai]

At Mon, 29 Jun 2009 13:10:53 +0100,
Daniel Drake wrote:
> 
> Hi,
> 
> I'm working on some sound issues with the new OLPC XO-1.5 alpha board.
> This laptop is now based on a VIA VX855 chipset and our board includes a
> CX20582-10Q HDA codec. We are running kernel v2.6.30.
> 
> We have a few issues, which are:
> 
> 1. Volume range is ridiculous, you can go all the way down to -74dB
> gain.  Beyond -42dB you can barely hear anything from the speakers, and
> I note that all my other systems only go down as far as -46.5dB.
> 
> 2. No microphone automute. The internal microphone continues recording
> sound while there is an external one plugged in.

The generic parser doesn't support this.  It gives only a few basic
functionalities, so far.

> 3. No speaker automute. The internal speakers continue playing sound
> while there are headphones plugged in.

Ditto.

> 4. Mixer arrangement is odd. There are 3 microphones: Mic, Mic 1, and
> Mic 2. Mic (the default) records nothing. Mic 1 and Mic 2 both seem to
> behave the same, and record from both internal and external microphones.

A similar issue.  Likely a problem of the generic parser.

> I looked into adding some quirks into patch_conexant.c to hopefully
> solve some of the above. However I note that there is no support for the
> CX20582, hence the generic HDA parser is being used. How has support for
> the other CX chips been developed -- are datasheets always required?

Ideally, yes.
If the codec tree looks similar as other Conexant codecs, you can adapt
patch_conexant.c...


Takashi