[LAU] [Bulk] Re: Bridging alsa and jack midi

[Tim E. Real]

On September 26, 2014 05:26:15 PM Rui Nuno Capela wrote:
> On 09/26/2014 04:12 PM, Philipp Überbacher wrote:
> > On Fri, 26 Sep 2014 10:50:06 -0400
> > 
> > Paul Davis <paul at linuxaudiosystems.com> wrote:
> >> On Fri, Sep 26, 2014 at 7:17 AM, Philipp Überbacher
> >> 
> >> <murks at tuxfamily.org> wrote:
> >>> On Thu, 25 Sep 2014 18:17:56 -0400
> >>> 
> >>> Paul Davis <paul at linuxaudiosystems.com> wrote:
> >>>> On Thu, Sep 25, 2014 at 4:56 PM, Philipp Überbacher
> >>>> 
> >>>> <murks at tuxfamily.org> wrote:
> >>>>> on as far as timing.
> >>>>> 
> >>>>> So I remember correctly that there used to be issues with -X
> >>>>> seq.
> >>>> 
> >>>> the -X seq option in current JACK1 is just a backward compatible
> >>>> hack to allow qjackctl and other tools to invoke the relevant
> >>>> stuff.
> >>>> 
> >>>> the actual implementation is nothing to do with the old -X seq
> >>>> code, and is actually a2jmidid converted into an internal client.
> >>>> Note that JACK2 could use this client too - its source code is
> >>>> even in the theoretically "shared" git repo for JACK tools.
> >>> 
> >>> Is there a new, recommended way to do the same thing? I only found
> >>> -X alsa_midi in the man page but it does not have the same effect.
> >> 
> >> the confusion here is that there are two sets of command line
> >> 
> >> arguments when you start JACK:
> >>     jackd [ SERVER OPTIONS ] -d BACKEND_NAME [ BACKEND OPTIONS ]
> >> 
> >> for better or for worse, some of the option letters (e.g. -X or -p)
> >> can occur as either server options or backend options.
> >> 
> >> in the "old" world, there was only -X as a backend option and it had
> >> two arguments ("seq" or "raw"). Both of them are basically not
> >> sensible to use because of the poor implementations they refer to.
> >> 
> >> in the new world, the preferable use of -X is as a server option:
> >>     jackd ... -X alsa_midi ... -d BACKEND ....
> >> 
> >> BUT ... given the legacy of qjackctl and other control apps which
> >> don't know about this, I hacked jack1 so that it would look for the
> >> the -X seq argument as a **backend** option and treat that as if the
> >> user had used the new form.
> >> 
> >> It would have been less confusing to have not done this, but that
> >> would have meant that it would be impossible/harder to use qjackctl
> >> to invoke this new MIDI bridge stuff, since it only knows about -X
> >> (seq|raw) as a backend option.
> >> 
> >> Alles klar?
> > 
> > Alles klar. Well, mostly. I guess that alsa_midi only makes sense
> > when alsa is used as a backend, so I don't quite see why it is a server
> > option instead of a backend option. Anyway, using the -X alsa_midi as
> > server option works.
> 
> on qjackctl settings, you can set the server prefix to "jackd -X
> alsa_midi" and leave the midi driver to "none", especially when NOT
> using "alsa" as the driver back-end.
> 
> hth.
> cheers


Finally is it truly time to move on from the alsa seq and raw drivers?

Rui, if ye have not already done so, would ye consider a wee update to qjctl
 to show these new slaves ?

Since both Jack 1 and 2 now have slaves, perhaps a drop down list
 of the slaves with checkboxes beside each for choosing which ones to use.

For good modern user experience and app development it would really help.

Thanks!
Tim.