[pulseaudio-discuss] [PATCH v2] alsa-mixer: Add support for "Headphone+LO" and "Speaker+LO"

[Tanu Kaskinen]

On Wed, 2014-11-05 at 12:06 +0100, David Henningsson wrote:
> 
> On 2014-11-04 11:53, Tanu Kaskinen wrote:
> > On Mon, 2014-11-03 at 07:20 +0100, David Henningsson wrote:
> >> diff --git a/src/modules/alsa/mixer/paths/analog-output-headphones-2.conf b/src/modules/alsa/mixer/paths/analog-output-headphones-2.conf
> >> index 74c467a..e29331b 100644
> >> --- a/src/modules/alsa/mixer/paths/analog-output-headphones-2.conf
> >> +++ b/src/modules/alsa/mixer/paths/analog-output-headphones-2.conf
> >> @@ -48,6 +48,14 @@ volume = off
> >>   switch = mute
> >>   volume = zero
> >>
> >> +[Element Headphone+LO]
> >> +switch = mute
> >> +volume = zero
> >
> > I think these should be "off". Why would you want to set the headphone
> > and lineout output to maximum when you start to use the headphones 2
> > jack? If both jacks are connected to speakers, things are going to get
> > loud...
> 
> AFAIK, I don't think the hda driver ever creates a "Headphone 2" volume 
> control. And the hda driver is the only one who ever creates a 
> "Headphone+LO" volume control.
> 
> So this is all very theoretical and is very unlikely to ever exist.
> But if it did, chances are that a "Headphone+LO" volume control would 
> also control the "headphone 2" path. And that all Line Outs would be 
> automuted.

Ok, you probably have a better idea than me which topology would be more
likely.

> >> diff --git a/src/modules/alsa/mixer/paths/analog-output-mono.conf b/src/modules/alsa/mixer/paths/analog-output-mono.conf
> >> index 87b5081..589d4ce 100644
> >> --- a/src/modules/alsa/mixer/paths/analog-output-mono.conf
> >> +++ b/src/modules/alsa/mixer/paths/analog-output-mono.conf
> >> @@ -45,6 +45,10 @@ override-map.2 = all-left,all-right
> >>   switch = mute
> >>   volume = zero
> >>
> >> +[Element Headphone+LO]
> >> +switch = mute
> >> +volume = zero
> >
> > Should be "off" for same reason as explained above.
> >
> >> +
> >>   [Element Headphone2]
> >>   switch = mute
> >>   volume = zero
> >> @@ -55,6 +59,12 @@ volume = merge
> >>   override-map.1 = all
> >>   override-map.2 = all-left,all-right
> >>
> >> +[Element Speaker+LO]
> >> +switch = mute
> >> +volume = merge
> >> +override-map.1 = all
> >> +override-map.2 = all-left,all-right
> >
> > Should be "off" (there are also other instances in this file where
> > elements aren't set to "off" when they should). This path is meant to
> > control a mono output jack. When Lennart wrote this file, he seemed to
> > think that the "Speakers" element would apply to the mono jack too, but
> > it doesn't sound likely to me.
> 
> So let's keep things consistent for this patch, and if you like to 
> change the behaviour, check with the AC'97 folks first, that actually 
> have one of these, if speaker is part of their mono paths or not?

I checked the samples in src/modules/alsa/mixer/samples, and none of the
samples had both Master Mono and Speaker, so this is most likely purely
theoretical. If you don't like the proposed change, then let's leave it
as it is.

-- 
Tanu