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

David Henningsson david.henningsson at canonical.com
Mon Nov 22 15:59:58 CET 2010

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?

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?

>> 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).

David Henningsson, Canonical Ltd.
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