[LAU] Jack & pulse...knickers in a twist.

Mac macdroid53 at gmail.com
Wed Jun 6 18:38:50 CEST 2018


On Wed, Jun 6, 2018 at 10:22 AM, Bill Purvis <bill at billp.org> wrote:

> On 06/06/18 14:12, Mac wrote:
>
>
>
> ....
>
> Apparently not. I tried "jack_control dps device surround71:PCH,0" and
> still got playback_1,_2. (There are also surround21, 41, etc. none of those
> changed anything either.)
> As for hdajackretask, when I tried to "Apply now" I got a device busy
> message. I didn't try "Install boot override".
>
>
>> In my case the real answer is I don't know. I tend to disable any
>> internal audio device to clear up one more thing that may interfere with
>> "real audio".
>>
>>
> I use qjackctl, so I'm not that familiar with the command line interface.
> In the Qjackctl settings panel, under advanced, it shows the 'system'
> output device,
> and also a field for number of channels. I had an 8-channel DAC connected
> a while back
> and setting channels=8 and restarting produced 8 system outputs. So it is
> possible.
>
> Looking at web pages for jack_control, I'd suggest trying:
>
>     jack_control dps device surround71LPCH,0
>     jack_control dps channels 7
>
> might be the answer?
>

Assuming the 'L" was a typo i changed the lines in the script to:

jack_control dps device surround71:PCH,0
jack_control dps channels 7

That produced the following error after attempting execute the second line:

DBus exception: org.jackaudio.Error.InvalidArgs: Invalid container address
'driver':'channels':'(null)' supplied to method 'GetParameterInfo'.

A look at the jack_control help showed the parameter was "outchannels:
Number of playback channels (defaults to hardware max) (uint:notset:0:0)"

I assume this means the surround71 knows only 2 channels, but I changed the
script:

jack_control dps device surround71:PCH,0
jack_control dps outchannels 7

This does not throw an error, but still only results in 2 system outputs.
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