(OM2008.8-update) (audio/GSM) alsamixer names

Daniel Hedblom daniel at solle.se
Tue Sep 16 07:20:13 CEST 2008


If someone could just write up their knowledge about the various mixer
items in alsa i think that would help a lot. I have been fiddling with
alsa for days on end but its a real maze. For example it would speed
up development of better defaults if people would post their working
state files.


2008/9/16 Vasco Névoa <vasco.nevoa at sapo.pt>:
> Hi.
> Some callers have been complaining my GSM microphone level is low, so
> I've been reading the threads about echo cancellation and alsa state
> files, but every time I walk into alsamixer I get lost.
> I'd like to suggest different names for the Alsa controls, because quite
> frankly I cannot relate to the ones I see in alsamixer. But first I'd
> like to ask you guys if you feel the same need as me. Do you feel
> comfortable with the present alsa channel names, or would you like them
> to be clearer?
> I think that these names are confusing and sometimes even misleading.
> They should be closer to the user... like for example, from (1) we know
> that the "Voice" interface is connected to the bluetooth interface; why
> not call it "bluetooth"?? The same goes for PCM; I know "everybody"
> knows that PCM means "Pulse Code Modulated" and that can only come from
> the CPU, but can't we make life easier on ourselves and call it CPU or
> SoC or System or something more obvious that says "this is Linux's sound
> card"? The Mic1 and Mic2 could be called HeadMic and BuiltInMic or
> something.
> This would make it clearer for everyone messing with these settings, and
> so would help accelerate the troubleshooting of this complex system.
> As to the more obscure controls, like the MUXers and the intermediate
> routing volume levels, I'd like them to be less distracting and more
> accurate; they are used for several things, so they should not be named
> for external objects; how about calling them their wolfson datasheet
> names, like "LMSEL"?...  this way we wouldn't need to constantly try to
> "decode" the meaning of each of these things, we'd just open up the
> picture (1) and everybody would know precisely what is being talked
> about...
> Basically, I'm trying to propose a naming scheme that separates
> "high-level stuff" (like plain Headphones and Microphone volume) from
> "low-level stuff"  (like routing in the mixers). This would allow us
> newbies to play in alsamixer without fear of breaking some obscure
> routing that may later come back to bite us in the ear.
> Does anyone know where the alsa channel names are defined (which file)?
> Oh, and I think I see a bug: the channel names "Headphone" and "Speaker"
> are exchanged, as far as I can see. Phone call volume is controlled via
> "Speaker" and SoC music play is controlled via "Headphone"; Isn't this
> supposed to be the other way around? Please confirm/deny.
> (1): http://wiki.openmoko.org/wiki/Neo_1973_audio_subsystem#ALSA_Channels
> Vasco Névoa.
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