Re: [Discuss-gnuradio] Help needed with message ports

[Volker Schroer]

Hi Michael,

thank you for your reply. Yes your clarification is correct.

The block I'm trying is of type hier2_block. Meanwhile I found an older post

https://lists.gnu.org/archive/html/discuss-gnuradio/2015-10/msg00008.html

 describing the same problem. But the gnuradio code has been modified 
since then, but it seems that the proposal in this post has been 
incorporated.


I tested with the current git/master and git/next. The problems are the 
same.

I think it depends on the hier2 block, as I can setup a simple flowgraph 
with a signal source ( this is of type sync block ) that works.

Now I'm trying to understand the code of 
hier_block2_detail::msg_connect. But at the moment this is hard stuff 
for me.
I'll report if I get a solution.

-- Volker




Am 21.07.2018 um 16:23 schrieb Michael Dickens:
> Hi Volker - Just to clarify:
>
> You've added an -optional- input async message port to a block that currently does just 
> streaming. If you -do not- try to connect to this new port, then everything works as desired 
> & as before. If you -do- try to connect to the port then you get the runtime error 
> "insufficient connected output ports (1 needed, 0 connected)". Yes?
>
> "Once upon a time" ... there was, and as it turns out still is (just tried using 
> the current GIT master of GR), a bug in the code that handles connections for mixed streams 
> and -input- async messages, which results in the runtime error you're encountering. I can 
> provide a very simplified OOT that shows this error; I tried to track it down once but got 
> sidetracked & never figured it out. Maybe I'll give it a go again this coming week ... 
> or, maybe you can?
>
> Sorry for the bad news! - MLD
>
> On Fri, Jul 20, 2018, at 6:28 AM, Volker Schroer wrote:
> > Hi,
> >
> > I'm trying to add an message port to my  working oot module fcdproplus
> > to be able to control the frequency by an message from a qtgui sink.
> >
> > I used the analog signal source as guide and implemented a message sink
> > in the grc description, registered the in port, and defined  a handler
> > function like described in the tutorial.
> >
> > I can run my example of a simple fm receiver as before, but when I
> > connect the message out port of a qtgui sink to my message in port of my
> > oot block,
> >
> > I get the following error message:
> >
> >
> > ./FMRadio.py
> > INFO: Audio source arch: alsa
> > Funcube Dongle Pro+ found as: plughw:3,0
> > Dongle sucessfully initialized
> > Result of Action :+++++
> > FCDAPP 20.03
> >    Lna gain enabled
> >    Mixer gain enabled
> > If gain set to: 10
> > Set Frequency to: 94.3 KHz, corrected to: 94300 Khz
> > INFO: Audio sink arch: alsa
> > Traceback (most recent call last):
> >     File "./FMRadio.py", line 277, in <module>
> >       main()
> >     File "./FMRadio.py", line 266, in main
> >       tb.start()
> >     File
> > "/usr/local/gnuradio/lib64/python2.7/site-packages/gnuradio/gr/
> > top_block.py",
> > line 109, in start
> >       top_block_start_unlocked(self._impl, max_noutput_items)
> >     File
> > "/usr/local/gnuradio/lib64/python2.7/site-packages/gnuradio/gr/
> > runtime_swig.py",
> > line 5678, in top_block_start_unlocked
> >       return _runtime_swig.top_block_start_unlocked(r, max_noutput_items)
> > RuntimeError: fcdproplus(3): insufficient connected output ports (1
> > needed, 0 connected)
> >
> > These are the connections:
> >
> >
> >          ##################################################
> >           # Connections
> >           ##################################################
> >           self.msg_connect((self.qtgui_sink_x_0, 'freq'),
> > (self.fcdproplus_fcdproplus_0, 'freq'))
> >           self.connect((self.analog_fm_demod_cf_0, 0),
> > (self.audio_sink_0, 0))
> >           self.connect((self.analog_fm_demod_cf_0, 0),
> > (self.audio_sink_0, 1))
> >           self.connect((self.fcdproplus_fcdproplus_0, 0),
> > (self.low_pass_filter_0, 0))
> >           self.connect((self.fcdproplus_fcdproplus_0, 0),
> > (self.qtgui_sink_x_0, 0))
> >           self.connect((self.low_pass_filter_0, 0),
> > (self.analog_fm_demod_cf_0, 0))
> >
> > If I remove the line
> >
> > self.msg_connect((self.qtgui_sink_x_0, 'freq'),
> > (self.fcdproplus_fcdproplus_0, 'freq'))
> >
> >
> > from my python script he error message disappears.
> >
> > What am I doing wrong?
> >
> >
> > Any help is appreciated.
> >
> > -- Volker
> >
> >
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