[alsa-devel] asihpi: Control naming

Sebastian H. vand2 at gmx.de
Thu Sep 30 23:28:46 CEST 2010

>>> "PCM 3 Capture Meter" is regarded as a playback control since it has
>>> an invalid (unknown) suffix.  If it's "PCM 3 Meter Capture Volume",
>> But it is not a volume, it is a level meter?!
>> We also have controls for tuners, microphones, equalizers, sampleclocks
>> etc.  Surely these can't be all "Volume" or "Switch"
>> I'm not sure why the suffix has any bearing on the direction?
> Actually, this control is handled as a "neutral" control without
> the directional attribute.  alsamixer or else may show it in the
> playback but also may show in capture, too.

This is interesting. In alsamixer-qt4 I've just stumbled over
enum elements for which both
snd_mixer_selem_is_enum_playback and
return 0/false (2.6.32 kernel emu10k1 chip).

May I drop the question in if this state can be considered valid
and besides *playback* and *capture* elements there's a third group of
*neutral* elements?

(On the other hand switches and volumes are always directed.)

Right now I handle it by dumping a warning message to stdout
and puting it into the playback direction element list.


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