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

[David Henningsson]

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).

>>  required-any = any
>> -switch = mute
>> +switch = select
>>  volume = merge
>>  override-map.1 = all
>>  override-map.2 = all-left,all-right
>>  
>> -[Element Capture]
>> +[Element Headphone Mic]
>> +required-any = any
>>  switch = mute
>>  volume = merge
>>  override-map.1 = all
> [...]
>> diff --git a/src/modules/alsa/mixer/paths/analog-input-internal-mic-always.conf b/src/modules/alsa/mixer/paths/analog-input-internal-mic-always.conf
>> index cd08531..e9c288e 100644
>> --- a/src/modules/alsa/mixer/paths/analog-input-internal-mic-always.conf
>> +++ b/src/modules/alsa/mixer/paths/analog-input-internal-mic-always.conf
>> @@ -39,6 +39,12 @@ state.unplugged = unknown
>>  state.plugged = no
>>  state.unplugged = unknown
>>  
>> +[Element Capture]
>> +switch = mute
>> +volume = merge
>> +override-map.1 = all
>> +override-map.2 = all-left,all-right
>> +
>>  [Element Internal Mic Boost]
>>  switch = select
>>  volume = merge
>> @@ -63,7 +69,6 @@ name = input-boost-on
>>  [Option Int Mic Boost:off]
>>  name = input-boost-off
> 
> Again, maybe Boost should be after both Internal Mic?
> 
>> -
>>  [Element Internal Mic]
>>  switch = mute
>>  volume = merge
>> @@ -76,12 +81,6 @@ volume = merge
>>  override-map.1 = all
>>  override-map.2 = all-left,all-right
>>  
>> -[Element Capture]
>> -switch = mute
>> -volume = merge
>> -override-map.1 = all
>> -override-map.2 = all-left,all-right
>> -
>>  [Element Input Source]
>>  enumeration = select
>>  
>> diff --git a/src/modules/alsa/mixer/paths/analog-input-internal-mic.conf b/src/modules/alsa/mixer/paths/analog-input-internal-mic.conf
>> index ae3e9a8..5424a1b 100644
>> --- a/src/modules/alsa/mixer/paths/analog-input-internal-mic.conf
>> +++ b/src/modules/alsa/mixer/paths/analog-input-internal-mic.conf
>> @@ -44,6 +44,12 @@ state.plugged = unknown
>>  state.unplugged = unknown
>>  required-any = any
>>  
>> +[Element Capture]
>> +switch = mute
>> +volume = merge
>> +override-map.1 = all
>> +override-map.2 = all-left,all-right
>> +
>>  [Element Internal Mic Boost]
>>  required-any = any
>>  switch = select
>> @@ -70,7 +76,6 @@ name = input-boost-on
>>  [Option Int Mic Boost:off]
>>  name = input-boost-off
> 
> Same comment here.
>  
> 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.


-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic