Re: [Discuss-gnuradio] switching between two flow-graphs / controlling two flow-graphs

[Tom Rondeau]

On Fri, Jul 29, 2011 at 9:33 AM, Edmar Candeia Gurjao
<address@hidden> wrote:
> Hi,
>
> there is a patch in the mailing list to this problem in the patch mailing
> list http://lists.gnu.org/archive/html/patch-gnuradio/2011-07/msg00001.html
>
> I have aplied and it works,
>
> Edmar


This patch was applied to the code in the tree. Is it not working?

Tom



> 2011/7/29 niaz ahmed <address@hidden>
>>
>> Hi,
>>
>> I am working on an application ( half duplex communication ) where i have
>> two flow graphs receiver and transmitter. the scenario is that the receiver
>> should always be running but when the application require to send something
>> the receiver flow-graph should be stopped at that time. the reason for the
>> receiver flow-graph to be stopped is obvious that it should not receive the
>> data it is sending. i am using laptop sound card (not usrp).
>>
>> i am trying to stop the receiver and start it once the transmitter queue
>> becomes empty but i am getting the following error when i restart the graph
>>
>> audio_alsa_source[plughw:0,0]: snd_pcm_hw_params failed: File descriptor
>> in bad state
>>
>>
>>
>>
>>
>>
>> class receive_graph(gr.top_block):
>>
>>     def __init__(self):
>>         gr.top_block.__init__(self)
>>
>>         self.rcvd_pktq = gr.msg_queue()
>>
>>      #
>>      #some processing blocks here
>>          #
>>
>>      self.connect(src,//blocks//,sink)
>>
>>
>> class transmit_graph(gr.top_block):
>>
>>     def __init__(self):
>>         gr.top_block.__init__(self)
>>         audio_rate =8000
>>         self.src = gr.message_source(gr.sizeof_char, msgq_limit)
>>
>>       #
>>      #some processing blocks here
>>          #
>>
>>     speaker = audio.sink(audio_rate, "plughw:0,0");
>>     self.connect(src,//blocks//,speaker)
>>
>>
>>
>>
>>
>> if __name__ == '__main__':
>>     try:
>>            fg1 = freceive_graph()
>>         fg1.start()
>>         fg= transmit_graph()
>>         fg.start()
>>
>>         try:
>>
>>
>>
>>         while True:
>>              message = raw_input("Enter a message to transmit (Ctrl-D to
>> exit): ")
>>              fg1.stop()              #here i am stopping the receiver
>> graph
>>             #
>>             #  here i am making pkt from the message
>>             #
>>             fg.src.msgq().insert_tail(pkt)
>>             if fg.src.msgq().empty_p():
>>                 fg1.start()
>>
>>
>>         except EOFError:
>>                print "\nExiting."
>>                fg.src.msgq().insert_tail(gr.message(1))
>>                fg.wait()
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> # Main python entry
>>
>>     except KeyboardInterrupt:
>>         pass
>>
>>
>>
>>
>>
>> --
>> Niaz Ahmed
>>
>>
>>
>> “We are always more anxious to be distinguished for a talent which we do
>> not possess, than to be praised for the fifteen which we do possess”    :
>> Mark Twain
>>
>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
>
>
>
> --
> ---------------
> Edmar Candeia Gurjão
> Universidade Federal de Campina Grande.
> +55 83 2101 1403
> http://ecandeia.dee.ufcg.edu.br
> http://pet.ee.ufcg.edu.br/
>
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>
>