[LAU] jackd core dumps in duplex mode

[Gerhard Zintel]

On Monday 03 August 2015, you wrote:
> On Sun, Aug 2, 2015 at 4:26 PM, Gerhard Zintel 
<gerhard.zintel at web.de> wrote:
> > jackd watchdog: timeout - killing jackd
> > Aborted (core dumped)
>
> You're device is likely configured incorrectly, so that JACK never
> actually gets woken up by the device, times out and deliberately
> kills itself.
>
> You need to use alsamixer or an equivalent to select the correct
> capture source on the device. This was a relatively common issue
> with Intel HDA chipsets a few years ago - I haven't been hearing
> about it as much recently.

Thanks a lot Paul for the pointer
Short story: jackd is running again in duplex mode. Case solved.

Nonetheless:
If no capture source is selected in alsamixer, why does capture only 
mode work in jackd without problems and times out as soon as duplex 
mode is selected? Strange.

Furthermore:
I tried to tune the settings in alsamixer before bothering the list. 
For weeks I tried all permutations in alsamixer and qjackctl without 
success. Today, after your response, I opened alsamixer again, two 
devices (Capture and Capture1) have been in Capture mode. I switched 
off both, switched only Capture into capture mode and jackd started 
in duplexmode without problems. Out of curiosity I tried to recreate 
the old behavior - no chance, it's not longer possible. Even if I 
switch on / off capture mode for both Capture devices and chose 
different hardware interfaces in qjackctl (hw:0 = HDA Intel PCA, 
hw:0.0 = VT2020 analog) jackd starts trouble-free for all 
combinations. I do not really know the culprit. Alsa and jackd are 
still black boxes to me.

Again, thanks a lot
Gerhard