HDA Intel/ALC269 microphone problem

HDA Intel/ALC269 microphone problem

[Mathieu Bouffard]

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Read a few bug reports (going back to 2009!) around where users couldn't 
use their microphone with HDA Intel/ALC269. I had one set up JACK for 2 
playback channels and 1 capture channel, make an .asoundrc to route 
everything to pulse which is started with a configuration only using 
module-jack-sink and module-jack-source, start it up and the microphone 
and the whole setup worked. But that's quite a hassle for a workaround!

I had suspicions that it was the stereo mic causing problem and forcing 
mono would work and it seems to be the case. I attached a patch, hoping 
that the fix might be as simple as forcing mono at the ALSA level, but I 
don't think it'll be that simple... Can someone more experienced see if 
more is needed, and if not then commit it?

(orig file is from 3.0-rc1 source)

-- 
Mathieu Bouffard<mbouffard fedoraproject org>


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Changelog: this is probably not the only fix needed here, see the FIXME comment. I don't have the hardware
to test this.
Signed-off-by: Mathieu Bouffard <mbouffard@fedoraproject.org>
--- sound/pci/hda/patch_realtek.c	2011-05-29 20:43:36.000000000 -0400
+++ sound/pci/hda/fixed_patch_realtek.c	2011-05-31 20:48:43.621911836 -0400
@@ -14659,8 +14659,14 @@
 
 static const struct hda_pcm_stream alc269_44k_pcm_analog_capture = {
 	.substreams = 1,
-	.channels_min = 2,
-	.channels_max = 2,
+	.channels_min = 1,
+	.channels_max = 1,
+	/* FIXME I read multiple bug reports where ALC269 users couldn't use their microphone. I had
+	 * one set up JACK with two channels for output, and only one for input then route
+	 * pulseaudio's sink/source to JACK as a test. It worked, it would seem as if this
+	 * ALC269 does not support stereo capture? The above is probably not the only fix needed
+	 * here, leaving it up to somebody more experienced.
+	*/
 	.rates = SNDRV_PCM_RATE_44100, /* fixed rate */
 	/* NID is set in alc_build_pcms */
 };

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