[alsa-devel] Fast Track Ultra mixer - opinions anyone?

Clemens Ladisch clemens at ladisch.de
Mon Apr 16 15:10:25 CEST 2012

Felix Homann wrote:
> IMO, the effect section on the FTUs really sucks. I can't believe that
> anybody can really use it in a reasonable way. So should we really add
> another 40 controls to the mixer which can cause a lot of pain when
> misadjusted (i.e. anything else but 0)?
> For those reasons I would prefer not to put effect support in the
> kernel. What do you think?

If you want to be able to use these effects at all, there must be _some_
way to access the controls.

Generic mixer programs like alsamixer are not really suitable for
complex devices; you'd need to write a custom mixer.

If you want to prevent the controls from showing up in alsamixer, set
their .iface to SNDRV_CTL_ELEM_IFACE_CARD instead of _MIXER.  (But if
these controls don't show up in alsamixer, you wouldn't be able to reset
them if they are misadjusted ...)

> Currently alsamixer does not report any dB changes when you change a
> control value.

Set the TLV.  For standard controls, the code reads the values from
the USB descriptors, but for control you create by hand, you have to
create these, too.


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