[alsa-devel] [PATCH] hda: In-Amp support for 92HD7xxx codecs.

Takashi Iwai tiwai at suse.de
Fri Jan 25 16:20:20 CET 2008

At Thu, 24 Jan 2008 23:06:46 -0500,
Matthew Ranostay wrote:
> Takashi Iwai wrote:
> > At Thu, 24 Jan 2008 11:54:02 -0500,
> > Matthew Ranostay wrote:
> >> Some 92HD7xxx codecs have amps on the ports to volume control and/or mute certain ports.
> >> Also this makes stac92hd71bxx unmute amps lines in the init not needed.
> >>
> >> Signed-off-by: Matthew Ranostay <mranostay at embeddedalley.com>
> > 
> > The patch will create more controls such as "Headphone Gain Playback
> > Control".  What would be a benifit to have both "Headphone" and
> > "Headphone Gain" controls?  I'd like to avoid redundancy if both
> > provide a similar functionality.
> > 
> Well as in the 92HD71Bxxx case it would be useless, but for 92HD73xx
> series where we have 
> two headphone outs which share the same DAC, you could control the
> gains/mutes for each HP port. 
> Same with the line-outs and speaker outs.

It's a difficult case.  We can implement all, but we should simplify
in a certain level.  IMHO, get rid of the current "Headphone" controls
that affect both HPs, but implement two "Headphone" volumes with index
(or "Headphone2" or whatever) to control individually.  We have a
Master volume for the total volume control.

> > Also, "Line In As Output Gain Playback Volume" is hard to understand.
> > Let's make it simple.
> > 
> Ok I can see your point here, "Line In As Output Gain Switch" is
> kinda no not needed now that I think about it(since if you switch a
> port to output it powers down the in-amp). 
> As for "Line In As Output Gain Playback Volume" it could be changed
> to "Line In as Output Volume" so that would be part of "Line In as
> Output" mixer, I think that would be more clear.

Yes, it's better (although still a bit cryptic).  Well, it's because
this function is really complicated after all...



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