Subject: 3.19 on Nokia n900: audio quality awful

From: [email-masked] (Pavel Machek)
Date: Thu, 29 Jan 2015 21:42:18 +0100

Hi!

> >> I did this:
> >>
> >> I'm not sure which one is "main" microphone and which is headset, but
> >> I guess 2V should be "close enough" to 2.5V to produce something
> >> different from zeros..?
> >>
> > Main or integrated is digital microphone which does AD conversion itself
> > and headset is analogue. If DMIC is without bias codec will sample plain
> > zeros from DMIC input but analogue input should always produce some random
> > LSB bits from codec's AD converter.
> > 
> > If codec produces zeros also from analogue input then I suppose codec
> > ADC is not powered up or similar. One way to hunt regression if
> > bisecting is not possible due reason or another is to dump and diff codec
> > registers from /sys/kernel/debug/regmap/ using both working commit
> >and head.

I tried 2.6.28... where recording was, but it does not support
regmap. Then I tried 3.14, but could not get recording to work there.

> >>  	tlv320aic3x_aux: tlv320aic3x at 19 {
> >> @@ -502,6 +504,8 @@
> >>  		DRVDD-supply = <&vmmc2>;
> >>  		IOVDD-supply = <&vio>;
> >>  		DVDD-supply = <&vio>;
> >> +
> >> +		ai3x-micbias-vg = <1>;
> >>  	};
> > This should be 2, i.e. 2.5 V according to
> > Documentation/devicetree/bindings/sound/tlv320aic3x.txt. I think 2 V is
> > too low for some headset mics and that was the reason for 2.5 V.

Ok, tried that, but no change.

> Can you also try this patch to correct the DAPM route for the rx51:

Yes, with the patch below (and dts updates I did) recording works.

Another interesting note is that audio quality is not that horrible
when playing 8 kHz, mono signal... it is mostly what I'd
expect. Playing 44.1kHz, stereo mp3 .. is not good.

Tested-by: Pavel Machek <[email-masked]>

Thanks,
									Pavel

> diff --git a/sound/soc/omap/rx51.c b/sound/soc/omap/rx51.c
> index 04896d6252a2..7f299357c2d2 100644
> --- a/sound/soc/omap/rx51.c
> +++ b/sound/soc/omap/rx51.c
> @@ -250,14 +250,14 @@ static const struct snd_soc_dapm_route audio_map[] = {
>  	{"FM Transmitter", NULL, "LLOUT"},
>  	{"FM Transmitter", NULL, "RLOUT"},
> 
> -	{"DMic Rate 64", NULL, "Mic Bias"},
> -	{"Mic Bias", NULL, "DMic"},
> +	{"DMic Rate 64", NULL, "DMic"},
> +	{"DMic", NULL, "Mic Bias"},
> 
>  	{"b LINE2R", NULL, "MONO_LOUT"},
>  	{"Earphone", NULL, "b HPLOUT"},
> 
> -	{"LINE1L", NULL, "b Mic Bias"},
> -	{"b Mic Bias", NULL, "HS Mic"}
> +	{"LINE1L", NULL, "HS Mic"},
> +	{"HS Mic", NULL, "b Mic Bias"},
>  };
> 
>  static const char * const spk_function[] = {"Off", "On"};
> 

-- 
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