[alsa-devel] Conexant CX20582 HDA codec support

Daniel Drake dsd at laptop.org
Mon Jun 29 14:10:53 CEST 2009


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.

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

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.

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?
(I'll try and get hold of one anyway)

Here is some more info.
codec dump

codec graph

lspci entry

verbose dmesg from probing

Any thoughts/input appreciated!

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