[alsa-devel] Request for Device ID addition : 6935G

Hector Martin hector at marcansoft.com
Sat Jun 13 18:11:15 CEST 2009

Takashi Iwai wrote:
> Hector, does it work on your machine?  If yes, there should be a
> slight difference between 6935G and 8930G...
Yes, the DMIC works fine here (in mono mode).

Karthik: please look in sound/pci/hda/patch_realtek.c and locate the
alc889_acer_aspire_8930g_verbs array. At the end, where it talks about
the "DMIC fix", find the last verb:

{0x20, AC_VERB_SET_PROC_COEF, 0x0003},

And change the value from 0x0003 to 0x0001 and see what that does.

If this works and you get some audio, make a stereo recording. You want
both channels to be of equal volume.

I suspect you have a mono mic on the left channel. I have a stereo
sum/difference mic (WTF) with sum on the right channel, so I tweaked the
setting to replicate the right channel to both. This would kill your
audio if your microphone is just a mono one on the left channel. Setting
0x0001 should get you standard stereo audio as it comes from the mic(s).
I think setting 0x0002 should get you what you want (left channel
replicated to both channels). If not, try setting 0x0000.

Takashi: if I'm right, we'll need two model entries instead of one and
we should probably split off the verb array into three (base, stereo
sum/dif mic fix, mono mic fix).

Hector Martin (hector at marcansoft.com)
Public Key: http://www.marcansoft.com/marcan.asc

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