[alsa-devel] My Codec: IDT 92HD75B3X5 issues

Takashi Iwai tiwai at suse.de
Thu Oct 1 15:30:16 CEST 2009

At Thu, 1 Oct 2009 14:07:03 +0300,
 Munzir Taha (=?utf-8?q?=D9=85=D9=86=D8=B0=D8=B1?=   =?utf-8?q?_=D8=B7=D9=87?=) wrote:
> On Yaum al-Arbi'a 10 Shawwal 1430 9:36:10 am Takashi Iwai wrote:
> > At Wed, 30 Sep 2009 08:18:31 +0300,
> > 
> > Hm, are you using pulseaudio?  Just to be sure, try like below:
> > 	% arecord -Dplughw -fdat -vv foo.wav
> Yes, pulseaudio is running according to ps -e output. I ran arecord command as 
> you said and no difference.


> > Also, does the patch below have any influence?
> I applied that patch (commented the line) but no influence.

Then it's not about ADC power-off feature.

> > Basically the signal path from the built-in mic is very simple, so
> > there is no much room to change...
> I really don't know but it's a very bad SNR in Linux. Now, could it be that in 
> Vista they are implementing a Noise cancellation somehow?

Possibly.  But in general, the digital-mic input is often better
quality than analog-mics.  I asked whether this appears in the
external mic, too.

One thing I haven't mentioned is the IDT vendor-specific verbs for
digital mic settings, such as rate, voltage, etc.  These are listed
in the datasheet publicly available.

> Another try: could it be an IRQ issue since I noticed before the alsa update 
> the irq is different
> -                      HDA Intel at 0xda100000 irq 22
> +                      HDA Intel at 0xda100000 irq 33
> -                      HDA ATI HDMI at 0xda010000 irq 17
> +                      HDA ATI HDMI at 0xda010000 irq 34

This is likely the influence of MSI, which is used newly as default.

> Now, for some obscure reason I got confused in my previous messages when I 
> told you the external mic is working after the update. It seems it's always 
> the internal mic that's recording and when I plug the external mic, it makes 
> no difference. Attached is the current alsa report.

Hm, that's odd.  Could you check whether enable_msi=0 option changes
the behavior?


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