[pulseaudio-discuss] [PATCH] alsa-mixer: Prefer moving "Capture" before moving boosts

[Arun Raghavan]

On Fri, 2013-08-02 at 15:43 +0200, David Henningsson wrote:
> On 08/02/2013 03:34 PM, Arun Raghavan wrote:
> > On Fri, 2013-08-02 at 15:19 +0200, David Henningsson wrote:
> >> Some HD-audio codecs (at least ALC269VB and ALC283) become quite noisy on
> >> high Mic Boost levels. So e g, if there is a "Mic Boost" and a "Capture"
> >> control, both ranging from 0 dB to +30 dB, you get better quality if
> >> "Mic Boost" is 0 dB and "Capture" is +30 dB, than the other way around.
> >>
> >> By changing the order in the configuration files, this patch makes us prefer
> >> leaving "Mic Boost" low and "Capture" high if the user selects a medium gain.
> >>
> >> (This is based on limited experience, and there is no guarantee that there are
> >> no sound cards that work the other way around, and therefore this patch could
> >> potentially regress quality on those machines. Hopefully those are fewer, so
> >> this is what we should default to.)
> > [...]
> >> diff --git a/src/modules/alsa/mixer/paths/analog-input-headphone-mic.conf b/src/modules/alsa/mixer/paths/analog-input-headphone-mic.conf
> >> index 688b8ac..3a19e01 100644
> >> --- a/src/modules/alsa/mixer/paths/analog-input-headphone-mic.conf
> >> +++ b/src/modules/alsa/mixer/paths/analog-input-headphone-mic.conf
> >> @@ -27,21 +27,21 @@ description-key = analog-input-microphone
> >>  required-any = any
> >>  state.plugged = unknown
> >>  
> >> -[Element Headphone Mic Boost]
> >> -required-any = any
> >> -switch = select
> >> +[Element Capture]
> >> +switch = mute
> >>  volume = merge
> >>  override-map.1 = all
> >>  override-map.2 = all-left,all-right
> >>  
> >> -[Element Headphone Mic]
> >> +[Element Headphone Mic Boost]
> > 
> > If we're doing this, might as well prefer Headphone Mic over Headphone
> > Mic Boost?
> 
> We could, but I'd rather have some sort of evidence/indication that this
> will actually make a difference first. For starters, it's unusual to
> have both "Headphone Mic" and "Headphone Mic Boost" on the same sound card.
> 
> Also, we're moving this around because we have empirical experience that
> hardware behaves this way, not because it is logical for hardware to do
> so. Hence I'd refrain from extending the same logic to other controls.
> 
> Btw, the reason I'm moving "Capture" rather than the Mic Boosts is that
> I remember sometimes boosts are labelled "xx Mic" instead "xx Mic
> Boost", even though they are boosts and could potentially work the same
> way (become noisy at high levels).

Fair enough.

[...]
> > Rest looks good to me.
> 
> Ok, can I push this one as it is then? There's nothing stopping us from
> switching "Headphone Mic" and "Headphone Mic Boost" too, if we want to
> do so later.

Yes, please go ahead.

-- Arun