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

[Takashi Iwai <tiwai@suse.de>]

At Thu, 7 Sep 2006 11:29:54 +0100,
Jochen Voss wrote:
> 
> Hi Takashi,
> 
> On Thu, Sep 07, 2006 at 12:09:05PM +0200, Takashi Iwai wrote:
> > > > > -- s1.sh -------------------------------------------------------------
> > > > > #! /bin/sh
> > > > > amixer set "PCM Capture Gain" 2
> > > > > amixer set "PCM Capture Gain" 0
> > > > > amixer set "PCM" 0
> > > > > amixer set "PCM" 80%
> > > > > ----------------------------------------------------------------------
> > > > > 
> > > > > -- s2.sh -------------------------------------------------------------
> > > > > #! /bin/sh
> > > > > amixer set "PCM Capture Gain" 0
> > > > > amixer set "PCM Capture Gain" 2
> > > > > amixer set "PCM" 0
> > > > > amixer set "PCM" 80%
> > > > > ----------------------------------------------------------------------
> 
> > > I used 'amixer set "PCM Capture Gain" 20' now in s2.sh only.  Was this
> > > the plan?  Result: there is now an audible crack when s2.sh is
> > > executed, but the volume before and after the cracks still seems to be
> > > the same.
> > 
> > The crack doesn't matter seriously, but just the volume.
> 
> The volume is the same.
> 
> Why is everything assigned twice (e.g. first 0 then 2) in this test?
> 
> > > I also tried something else: when I alternate between
> > > ----------------------------------------------------------------------
> > > amixer set "PCM Capture Gain" 0
> > > amixer set "PCM Capture Gain" 20
> > > amixer set "PCM" 0
> > > amixer set "PCM" 80%
> > > ----------------------------------------------------------------------
> > > and
> > > ----------------------------------------------------------------------
> > > amixer set "PCM" 0
> > > amixer set "PCM" 80%
> > > amixer set "PCM Capture Gain" 0
> > > amixer set "PCM Capture Gain" 20
> > > ----------------------------------------------------------------------
> > > the recording has alternating load and quiete stretches.  Whatever this
> > > might tell us about the ADC, it looks like a bug to me: the order of
> > > setting the two controls shouldn't matter.  Or am I confused again?
> > 
> > Well, assume that "PCM Capture" and "PCM Capture Gain" are
> > independent.  If so, the above two should result in the same state.
> > 
> > If it's not independent but the register 4 & 5 take single values
> > (that was the behavior of your original implementation), the above two
> > cases must make a clear difference: in the former case, the gain is
> > below 0dB, and in the latter it's +10dB.  Was it so through your
> > tests?
> 
> Yes, the recording had alternating load and quite stretches,
> corresponding to the two settings.
> 
> So both tests seem to indicate that for the AK5365 registers 4 and 5
> take only a single value.  Correct?

Yes.  Then we need to take the controls back to a single one.
Will do later.

I still wonder whether this is also true for AK4524...


> > Also, it's possible that I did make a silly mistake.  Put a debug
> > printk around ak->ops.write() in snd_akm4xxx_write() to check what
> > values are written to register 4 and 5.
> 
> I will try this in the evening.

Thanks,


Takashi

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