Re: [RFC] Add dB scale information to AK4xxx codec

[Takashi Iwai <tiwai@suse.de>]

At Mon, 4 Sep 2006 18:41:24 +0100,
Jochen Voss wrote:
> 
> Hi Takashi,
> 
> On Mon, Sep 04, 2006 at 12:13:06PM +0100, Jochen Voß wrote:
> > > Hm, there is no "PCM Capture Gain Capture", maybe "PCM Capture Gain
> > > Volume"?  It's IPGA.
> > I will send the amixer output this evening when I get back home.
> 
> Ok, it seems to be a problem with alsamixer (maybe caused by the fact
> that I still used v1.0.11).  The amixer output looks better and does
> not have the strange "PCM Capture Gain Capture".  My apologies for the
> confusion caused.

OK, maybe the problem is its naming.
What happens if you change it as "PCM Gain Capture Volume"?
Then you'll get "PCM Gain" in the capture section of alsamixer.

Anyway, I'd like to know whether IPGA and IATT are really independen
on AK5365 codec chip.  Try to compare the volumes recorded in the two
conditions:
	IPGA = non-zero, Capture = below 0dB (e.g. 80%)
and
	IPGA = 0 (=0dB), Capture = same value as above

In both cases, make sure that you "reset" the volume, that is, once
set the volume to 0 (or else) then set to another target value.
The sequence to test is to first set IPGA (Capture Gain) then set
Catpure Volume.  You can use amixer,

	% amixer set "PCM Gain" 2
	% amixer set "PCM Gain" 0
	% amixer set "Capture" 0
	% amixer set "Capture" 80%
	recording...

	% amixer set "PCM Gain" 0
	% amixer set "PCM Gain" 2
	% amixer set "Capture" 0
	% amixer set "Capture" 80%
	recording...

If the volumes of two cases are same, the IPGA isn't independent and
both controls should be merged to a single control.


Takashi

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