[pulseaudio-discuss] [PATCH] alsa-mixer: sb-omni-surround-5.1.conf: remove analog-surround-21, add Linux 4.3+ support

Nazar Mokrynskyi nazar at mokrynskyi.com
Sat Jan 16 00:26:51 PST 2016

OK, I've spent another hour or so trying different combinations and it 
seems to be a bug inside either ALSA or PulseAudio.
SB Omni Surround 5.1, as you can see from name, has 6 outputs: 
front-left,front-right,rear-left,rear-right,front-center,lfe (lets 
ignore other non-related inputs/outputs here)
I've done many experiments and defined which modes are working and which 

Modes that work fine:
- 5.1
- 5.0
- 4.0
- 2.0

Modes that doesn't work fine:
- 2.1 (stereo only, noise in 3rd output starting from 1 instead, 
relatively hight frequency light clicking)
- 4.1 (quadro only, noise in 5th output starting from 1 instead, 
relatively hight frequency light clicking)

It is clearly visible that any time I want to skip some output, for 
     ttable.0.FL 1
     ttable.1.FR 1
     ttable.5.LFE 1
instead of
     ttable.0.FL 1
     ttable.1.FR 1
     ttable.2.LFE 1

To direct LFE to proper output it doesn't work. This is the same reason 
why 5.0 is working fine (no skipped outputs, all consequent) and 4.1 
doesn't (we need to skip 5th output starting from 1 and use 6th instead).

When I try this:
     ttable.0.FL 1
     ttable.2.FR 1
     ttable.1.LFE 1
then as expected I can hear LFE in right front output.

Any hints from anyone what is wrong here? There are literally NO DOCS 
about how it works internally, so these experiments all I can provide at 
the moment.
There were pulseaudio logs in this thread if anyone needs details.

ALSA 1.1.0, PulseAudio 7.1, Ubuntu 16.04 x64

Sincerely, Nazar Mokrynskyi
Skype: nazar-pc
Diaspora: nazarpc at diaspora.mokrynskyi.com
Tox: A9D95C9AA5F7A3ED75D83D0292E22ACE84BA40E912185939414475AF28FD2B2A5C8EF5261249

On 28.11.15 09:56, Raymond Yau wrote:
> >
> > I've been looking at those lines. Do you think it should be done in 
> USB-Audio, or should it be added into separate config file specific 
> for this sound card?
> http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/conf/pcm/surround21.conf;hb=HEAD
> The route of surround21 is hardcoded to use surround51 , this mean 
> your ttable are used by those usb audio support 6 channels, those usb 
> audio which only support 8 channels need to define their own 21 route 
> as both surround51 and surround71 of usb audio use route plugin
> _______________________________________________
> pulseaudio-discuss mailing list
> pulseaudio-discuss at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss

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