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

[Takashi Iwai]

At Mon, 20 Oct 2014 11:59:30 +0200,
David Henningsson wrote:
> 
> 
> 
> On 2014-10-20 11:55, 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.
> >  >>  >
> >  >>  >
> >  >>
> >  >> http://shop.lenovo.com/us/en/desktops/thinkcentre/a-series/a58/
> >  >>
> >  >> The technical specification of a58
> >  >>
> >  >> 2 pin internal speaker connector
> >  >> Alc662 5.1
> >  >>
> >  >> https://bbs.archlinux.org/viewtopic.php?id=156433
> >  >>
> >  >> Seem windows support surround 5.1
> >  >
> >  >
> >  > Raymond, there can certainly be cases which this patch does not cover
> > - after all, it's mostly a band aid given the lack of topology
> > information - but do you see cases where this patch actually causes a
> > *regression*? If so, could you point me to alsa-info for the machine
> > where this patch causes a regression?
> >  >
> >
> > www.realtek.com.tw/products/productsView.aspx?Langid=1&PNid=24&PFid=27&Level=5&Conn=4
> > <http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PNid=24&PFid=27&Level=5&Conn=4>
> >
> > I expect those desktop with 2+2 HD Audio codec support independent headphone
> >
> > This mean the driver should not create "Lineout+HP" Playback volume
> >
> > Line out and headphone cannot share same DAC
> 
> I doubt that, but if they cannot share the same DAC, that needs to be 
> addressed in a separate patch. This patch just deals with the naming, 
> given that the previous logic has determined that headphone and Line out 
> should share the same DAC.
> 
> Takashi, are you planning to apply this patch? Or are you looking for 
> more testing first?

I'll test a bit more.  I have a machine that is affected by this
issue, so I can test on a real machine.

How about the changes in PA side, BTW?  Is it ready?


Takashi