Simplifying the mixer

[Joerg Reisenweber]

Am Do  12. Juni 2008 schrieb andrzej zaborowski:
> On 12/06/2008, Joerg Reisenweber <joerg at openmoko.org> wrote:
> > Let me straighten this out a little more:
> >  Our headphones and our speaker "path" share the same physical elements 
like
> >  amplifier and volume control. So there never will be a separate control 
in
> >  alsamixer for master level of headphone and another one for speaker 
(unless
> >  someone will hack the alsa-driver). Instead the one control changes it's
> >  meaning depending on another control that actually does the switching
> >  hp<->spk.
> 
> Well, that's like my desktop: it has a PCM master control that
> controls generic playback volume no matter where it goes. 
> Then it has 
> one stereo control for the speakers and one for the headphones and
> other outputs,

You simply won't see this in alsamixer for gta03. It doesn't exist, unless 
your mixer app emulates it. THERE IS *NO* CONTROL FOR HEADPHONES *ONLY*

Didn't I tell there's exactly one hardware level control for two outputs?!
You're still thinking "path" and obviously didn't look at the mixer diagram at
http://www.wolfsonmicro.com/uploads/documents/en/WM8753.pdf

> the output volume is the product of all the controls on 
> the path.

That's pretty obvious and always true. But doesn't help.


> 
> > What would you suggest for this very simple(!) case to name the
> >  control: "Speaker Vol", "Headphones Vol", "Speaker/Headphones",
> >  "OUT1VOL"? The first 3 names are ambiguous or even incorrect, the 4. will 
give
> >  a clue to everyone who is trying to understand what is really going to 
happen
> >  when this control is changed.
> 
> "PCM" or "Playback" or something.

Or something. :-P Why not "applepie"? This has ABSOLUTELY NOTHING to do with 
PCM! BTW: PCM is already used - for PCM :-D Just we got no digital elements 
during call, so OT.
And you think "Playback" is a good intuitive description for the volume of 
your phone's earpiece???

> >
> >  Any higher sophisticated userland app could/should use the scenario 
services
> >  and knowledge about currently active "path" to rename "OUT1VOL"
> >  to "Speaker/Headphone Volume", or even provide two distinct
> >  controls "Headphone" AND "Speaker" and store the setting of the actually
> >  inactive one, while applying the other one to OUT1VOL mixer-element. 
So "the
> >  user" never gets in contact with technical names, while "low level 
hackers"
> >  aren't puzzled by wrong simple path related names.
> 
> I don't know.. I use alsamixer and aumix on my desktop, they both work
> with the ALSA mixer controls 1:1 - no remapping, there's no reason
> alsamixer should be a hacker-only thing on GTA02.

So do me a favor and use alsamixer on the ssh of GTA01/02, and then tell me 
whether you succeeded to understand *and* *use* the controls there, the way 
they are named right now. alsamixer is no hackertool, it is even worse, in 
conjunction with our alsa-soundcard-driver it's a poor tool with WRONG NAMES 
even hackers like me don't like to use. I tried to explain why it can't be 
fixed when we don't abandon the "path" thinking. Obviously I failed on it, at 
least for you. Please accept that Wolfson mixer is much more powerful but 
also much more complex than your primitive AC97-sound-hw inside your 
desktop-PC It has 12(!) inputs and 11(!) outputs and a complex way to connect 
virtually everything to everything, even more than one path per 2 endpoints.
When I try to level the earpiece volume and start alsamixer for that purpose, 
you really suppose I directly find "PCM"(your suggestion) to be the right one 
of the >90(!) controls in there - even when sound during call has no PCM 
thing at all??? :-/ Sorry, obviously you must be kidding.

 
> 
> In general I think Linux is more flexible than you're thinking 

Believe me, I have a decent idea of the flexibility of unix-systems - about 18 
years now, and I messed around with ALSA for some years. So I won't quote 
your very common facts of the following eleven lines.

> >  NB: even a cryptic technical name with register-annotation is better than 
> >  a completely false name, especially for "the user". It doesn't provoke
> >  frustration of the kind "It's so simple to understand, but it just 
> >  doesn't work"

If you think about answering this mail, please first try to figure out 
what 'Voice Sidetone Capture Volume' control is going to change exactly on 
Wolfson mixer, and what's the difference to 'Sidetone Capture Volume'  
control. If you also tell me then, for which specific scenario your findings 
are valid, maybe we might continue to discuss this topic of "simple names" in 
alsamixer (which is NO hackertool even though it does no renaming XD. You 
just have to study the alsadriver source code to understand the controls).

/jOERG
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