Re: [Jack-Devel] Jack2 alsarawmidi slave: Pluggable device registration problem?

Hi Tim,

On Sat, Sep 27, 2014 at 4:47 PM, Tim E. Real <[hidden]> wrote:

> When I plug in my USB midi device after starting Jack2 with alsarawmidi,
>  it does not register at all, as jack_lsp shows.

That's because the driver doesn't detect new devices.  It looks at the
devices that are connected when you start JACK, and assumes that those
are the devices that will be used.  I took this approach when I wrote
the driver because, at the time (it may still be this way), there
wasn't an elegant way to detect new devices using ALSA's rawmidi
interface.  I believe the ALSA sequencer interface has an event
mechanism for new devices; the rawmidi interface, in contrast, has no
such mechanism.

> But then if I unplug the device, strangely the ports do not unregister and
> I can even make connections to them in qjctl.

I'm not surprised that the ports don't disappear, but I am surprised
that there isn't a bunch of (poll-related) error messages that flood
your JACK console.

I'm happy to help brainstorm on ideas about how to best solve the
problem.  I can't guarantee that I'll find time to actually fix the
problem if and when a reasonable solution pops up.

Thanks,

-- 
Devin Anderson
surfacepatterns (at) gmail (dot) com

blog - http://surfacepatterns.blogspot.com/
midisnoop - http://midisnoop.googlecode.com/
psinsights - http://psinsights.googlecode.com/
synthclone - http://synthclone.googlecode.com/

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