[alsa-devel] [RFC PATCH 1/2] ALSA: hda - Fix "PCM" name being used on one DAC when there are two DACs

[Takashi Iwai]

At Sat, 18 Oct 2014 20:33:49 +0800,
Raymond Yau wrote:
> 
> >> >
> >> > In the scenario where there is one "Line Out", one "Speaker" and one
> >> > "Headphone", and there are only two DACs, two outputs will share a DAC.
> >> > Currently any mixer on such a DAC will get the "PCM" name, which is
> >> > misleading. Instead use "Headphone+LO" or "Speaker+LO" to better
> >> > specify what the volume actually controls.
> >>
> >> Are there any examples ?
> >>
> >
> > I used "hda-emu
> codecs/canonical/alc3226-dell-precision-m2800-ccert-201404-14986 -i 1" when
> developing the patches.
> >
> > I don't have any hardware available myself that exposes this behavior,
> but I can maybe fake one with hdajackretask, if that counts...
> >
> 
> How about adding these names to slaves of virtual master volume/switch ?
> 
> hdajackretask won't help if the topology of the codecs are  different
> 
> Seem the badness still prevent the driver to support surround 5.1 with
> three rear panel jacks, internal speaker and front panel headphone for
> Thinkcenter A58 using alc662
> 
> https://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg29203.html
> 
> Why 3stack desktops with 6 channels codecs not using  "Headphone+LO"  or
> "Speaker+LO" ?

The problem is just the lack of DACs, so it cannot cover all three
outputs, no matter how the pins are chosen.  That is, it's no 6
channels at all but 4 channels at most.


Takashi