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

Vasco Névoa vasco.nevoa at sapo.pt
Tue Sep 16 03:55:26 CEST 2008


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 

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 

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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