[alsa-devel] Verifying mixer dB data/Invalid dB data from USB cards, especially Aureon 5.1 MkII

Lennart Poettering mznyfn at 0pointer.de
Tue Feb 23 23:32:34 CET 2010

On Tue, 23.02.10 11:08, Clemens Ladisch (clemens at ladisch.de) wrote:

> Lennart Poettering wrote:
> > On Sun, 21.02.10 12:01, Raymond Yau (superquad.vortex2 at gmail.com) wrote:
> > > However Simple Mixer API cannot know the subdevice number , you have to use
> > > control API ( the lower level API used by Simple Mixer API )
> > 
> > Unfortunately there is no way from the simple mixer to the lower level
> > mixer.
> >From the check_unplugged function in alsa-utils/alsamixer/mixer_widget.c:
> 	err = snd_mixer_get_hctl(mixer, mixer_device_name, &hctl);
> 	if (err >= 0)
> 		ctl = snd_hctl_ctl(hctl);

But that still doesn't give me a hint which snd_ctl_eleme_t belongs to
which snd_mixer_eleme_t, does it?

> > It would be great if the smixer would include some API that gives me a
> > hint to which device/subdevice a specific snd_mixer_elem_t belongs to.
> Often, there is no 1:1 correspondence between mixer elements and PCM
> devices.  Only mixer controls with interface PCM (not MIXER) have (sub-)
> device numbers, and at the moment this is used only for controls that
> are associated with the streams of hardware-mixing-capable cards.

Which are not that many, right? Not HDA at least?

> Getting information about the mixer layout (like the nodes reported by
> HDA and USB devices) is on the TODO list; the only reason it isn't being
> implemented is lack of time.

Would be great to have that.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

More information about the Alsa-devel mailing list