[alsa-devel] [PATCH 2/3] ALSA: HDA: Rename "Front" to "Master Front" on ALC861VD and ALC887

[Takashi Iwai]

At Mon, 22 Nov 2010 15:59:58 +0100,
David Henningsson wrote:
> 
> On 2010-11-22 09:51, Takashi Iwai wrote:
> > At Mon, 22 Nov 2010 09:42:46 +0100,
> > David Henningsson wrote:
> >>
> >> On 2010-11-22 07:50, Takashi Iwai wrote:
> >>> At Fri, 19 Nov 2010 10:29:37 +0100,
> >>> David Henningsson wrote:
> >>>>
> >>>> Since "Front" controls headphones as well on these two codecs,
> >>>> they should be labeled "Master Front" in order to be handled correct
> >>>> by PulseAudio.
> >>>
> >>> Well, "Front" doesn't mean the physical output but rather the output
> >>> channels.  So, it doesn't conflict with the fact that this control
> >>> actually changes all outputs, as long as the output jacks are of front
> >>> channels.  In that sense, even "Surround" is also a sort of Master
> >>> control.
> >>>
> >>> That being said, I'm not happy with this rename.  If any, we should
> >>> try to get rid of unnecessary front volume control.  But, just because
> >>> PA gets confused doesn't sound like a right reason.
> >>>
> >>> Could you give the alsa-info.sh output for checking what mixer elements
> >>> are created?
> >>
> >> As you know PulseAudio needs consistent naming of volume controls, and
> >> this is not expressed clearly enough in the docs, so, what would you
> >> call a volume control that controls a front-line-out, but does not
> >> control a front-speaker or a front-headphone?
> >
> > What do you mean "front" in this context?  Is it the front 2 channels
> > out of 4.0 or 5.1 output?  Or do you mean the physical location of
> > the output?  Front/Surround/Center/LFE are the former case.  They are
> > controls independent from the physical output locations (per
> > definition).
> >
> > I guess this confusion came up because of the mix-up with front
> > channel and front panel.  We've used "Front Mic" in some places, for
> > example, which increases the confusion.
> 
> Good point. I think the reasoning so far is to refer to channels for 
> output and location for input.
> 
> Anyway, what I meant was "Front" channel (not location), so let me 
> rephrase my question into two:
> 
> 1) If I find a volume control (or mute switch) labeled "Front", should I 
> assume that it controls, or does not control, headphone output? How 
> about internal speakers?

Yes, this should be applied to all outputs in general.
(There might be some misuses, though...)

> 2) Assume I have a volume control (or mute switch) which controls only 
> the front line-out, not headphones, and not speakers. How should I name it?

A good question.  We should have a unified prefix for the location.
IIRC, "Front Line-Out" or "Front XXX" are used indeed, so far.

> >> PulseAudio assumes that if
> >> a control is named "Front", it does just that. So that's why I would
> >> prefer a rename to "Master Front".
> >>
> >> As for alsa-info output, I believe anything in hda-emu/codecs/alc861vd-*
> >> would do, as they have nsteps=0 on NIDs 0x0c - 0x0f.
> >
> > Yeah, the output with your first patch would be helpful.
> 
> Unfortunately I don't have access to the actual hardware at the moment, 
> so I'm attaching a codec dump from the hardware before the patch. 
> Running it against current HEAD, with today's patch from Kailang in, 
> probably makes hda-emu take the wrong code path (since hda-emu can't 
> read proc coefs).

Indeed, something is still fishy there.
OK, we need to fix it again...


thanks,

Takashi