[Jack-Devel] Failures in connecting mac OSX Sierra and an embedded board with linux via netjack2

[Chris Caudle]

On Tue, May 2, 2017 8:11 am, Frodo Jedi wrote:
> Regarding your questions, I have never truncated the commands outputs.

OK, maybe the coreaudio backend just doesn't dump out as much information
as the ALSA backend.  Just looks odd because on an ALSA machine you
usually get confirmation of what format and sample rate was set (sometimes
the hardware does not support what you requested, and the ALSA backend
will adjust to find the closest setting allowed by the hardware).

> I did various trials, I report the outputs below.

I see some variations in output even when it looks like the jackd
parameters are the same.  I don't quite understand why that might happen.

Trial 1 and 2 show this:

> TRIAL 1 ----------------------------------------------------
> On the master (Mac computer)
> sh-3.2# jackd -P 70 -p96 -t 2000 -dcoreaudio  -s -r48000 -p128 -n2 -Cno
> -Pyes
...
> CoreAudio driver is running...
> Starting Jack NetManager
...
> Floating point exception: 8

So after netmanager is loaded jackd dies with an exception.  Searching
google references to that exception number indicates that it can be
triggered by divide by 0 errors for integer or floating point, it is not
exclusively a floating point error.

Trial 2 looks like the same startup parameters were used for jackd, but no
exception that time, but the netmanager crashes with bad socket
parameters:

> TRIAL 2 ----------------------------------------------------
> On the master (Mac computer)
> sh-3.2# jackd -P 70 -p96 -t 2000 -dcoreaudio  -s -r48000 -p128 -n2 -Cno
> -Pyes
...
> CoreAudio driver is running...
> Starting Jack NetManager
> Listening on '225.3.19.154:19000'
> Sending parameters to ...
> Can't set net buffer sizes : Invalid argument
> SetParams error...

I don't see anything on the jackd command line to explain why they failed
in two different ways.
I think someone with more experience with jackd on Mac will need to chime in.

I don't think you need to spend any time even starting jack on the odroid
yet.

> TRIAL 1 ----------------------------------------------------
> On the master (Mac computer)
...
> Floating point exception: 8

> TRIAL 2 ----------------------------------------------------
> On the master (Mac computer)
...
> SetParams error...
> Can't init new NetMaster...

> TRIAL 3----------------------------------------------------
> On the master (Mac computer)
...
> Sending parameters to ...
> Can't set net buffer sizes : Invalid argument
> SetParams error...
> Can't init new NetMaster...

> TRIAL 4 ----------------------------------------------------
> The result are the same of before.,...

> TRIAL 5 ----------------------------------------------------
> On the master (Mac computer)
> Floating point exception: 8

> TRIAL 6 ----------------------------------------------------
> Can't set net buffer sizes : Invalid argument
> SetParams error...
> Can't init new NetMaster...

You obviously are not going to be able to get the odroid to connect to the
Mac until jackd can start the netmanager without crashing on the mac.

Nothing obvious stands out as a cause, what is needed is more verbose
output from jackd to help determine the underlying cause of the crash in
netmanager.

I don't know how directly comparable the messages from a linux computer
are to a mac build, but I had some trouble getting multicast packets
passed between machines, you may see if omping is available for MacOS, it
will verify that multicast traffic is enabled between the two devices.  I
had to build it for my ARM device running debian, it was available from
the Fedora repositories for my workstation.  Building from source was
simple on my ARM device, I just copied the source over and ran make, no
configuration necessary.

This article indicates that multicast is not enabled by default on MacOS:
http://blogs.agilefaqs.com/2009/11/08/enabling-multicast-on-your-macos-unix/

That article is several years old, it may not be accurate for current
versions of MacOS, but definitely something to check.   On my linux
machines I got output messages to the effect that there seemed to be a
network problem, which is the point I went off and found omping and
figured out my firewall problems.  The messages on MacOS don't seem nearly
as helpful.

-- 
Chris Caudle