[pulseaudio-discuss] Making PulseAudio harmonize with Intel HDA Mixer

[David Henningsson]

On 10/14/2011 07:18 PM, Soeren D. Schulze wrote:
> I am running PulseAudio on my laptop (Asus P50IJ) that has an Intel HDA
> card (chipset VIA VT1708S, Linux 3.0.0, Debian wheezy).

VIA codecs are not that common. That's the main reason (I assume) its 
chipset drivers are not as well standardised as Realtek or IDT ones are.

> The card basically has four mixer elements:
> 1. "Master Front", which controls the master volume
> 2. "Headphone", which does not seem to be doing anything
> 3. "PCM" -- obvious
> 4. "Front" -- similar to "Master Front", see below
>
> The right way to adjust the volume (in alsamixer) is:
>
> - When you want to use the built-in speakers, you need to adjust "Master
> Front" or "Front". PulseAudio adjusts "Front", which works. The only bad
> thing is that is ignores "Master Front" completely, so when it's at low
> volume by accident, you have to open alsamixer in order to fix the problem.
>
> - When you want to use headphones, the card is a bit strange: You need
> to *mute* "Front" to turn the built-in speaker off. But apart from that,
> both "Master Front" and "Front" still have the same effect as for the
> built-in speakers, so you must not turn the volume of "Front" down, even
> though it is muted. PulseAudio controls the "Headphones" element,
> though, which does nothing, and it sometimes un-mutes "Front",
> accidentally turning on the built-in speakers (which might be really
> unpleasant in some situations).
>
>
> Is there any canonical way out of this?

Funny you would use that wording, because here at Canonical [1] we have 
actually a patch that handles "Master Front"! [2] I don't remember 
exactly why Colin said this shouldn't be upstreamed, but I think it was 
related to Takashi not liking "Master Front" or something.

> Is it PulseAudio that I need to
> configure or is it the driver that needs fixing?

If the "headphone" volume control does not control the headphone volume, 
then that's a clear driver bug. I also remember an oddity in the driver 
actually toggling the "Front" mute flag when you plugged/unplugged 
headphones. When PulseAudio picks this up things can be a little bit 
unexpected...

And btw, avoid the "Independent HP" switch (set it to False/Off). It 
doesn't work well with Pulseaudio, unless you configure sinks by yourself.

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

[1] TBH it might just as well have been an Ubuntu volunteer who added 
the patch, but I didn't want to ruin the pun ;-)

[2] 
http://bazaar.launchpad.net/~ubuntu-audio-dev/pulseaudio/ubuntu.oneiric/view/head:/debian/patches/0007-handle-Master-Front.patch