Re: [Discuss-gnuradio] lock and unlock with transmit h_path and receive_path‏

[Veljko Pejovic]

Hi,

I have a similar problem in my code.
I modified benchmark_tx.py from gnuradio-examples/ofdm and ofdm.py
from blks2impl so that I can change the number of active subcarriers
on fly.

In the packet sending loop of benchmark_tx I periodically do the following:

lock the top block (tb.lock()), call a function in ofdm.py which
disconnects the blocks within ofdm_mod:

        self.disconnect((self._pkt_input, 0), (self.preambles, 0))
        self.disconnect((self._pkt_input, 1), (self.preambles, 1))
        self.disconnect(self.preambles, self.ifft, self.cp_adder,
self.scale, self)

rebuild them according to the parameters that I pass from
benchmark_tx and reconnects them. After that I call tb.unlock().

What happens is that sometimes it works, and sometimes it gets stuck
(some sort of deadlock I assume). I tried swapping lock-unlock with
stop-wait-start and that results in similar behavior (it actually goes
a few iterations further on average). I also tried moving lock-unlock
to the actual function in ofdm_mod, but that didn't change anything.

Any suggestions?

Thanks,


Veljko

2010/2/8 Eric Blossom <address@hidden>:
> On Sun, Jan 24, 2010 at 02:21:12PM +0100, Carlo Donato Lecce wrote:
>>
>> Hello all,
>>
>>
>> I seem that using transmit_path and receive_path the reconfigure
>> of flow graph is bad.
>> The following code hung after the call of unlock.
>>
>> I think that there are a bugs in the transmit_path because
>> using a gr.null_source insted of transmit_path the program not hangs.
>>
>> Thanks,
>>
>>
>> Carlo.
>
> Carlo,
>
> It looks like you're missing the calls to connect that would have your
> top block know about the nested blocks.
>
> See below.
>
> Eric
>
>
>> from gnuradio import gr, gru, modulation_utils
>> from gnuradio import eng_notation
>> from gnuradio.eng_option import eng_option
>> from optparse import OptionParser
>>
>> import random, time, struct, sys, math
>>
>> # from current dir
>> from transmit_path import transmit_path
>> from receive_path import receive_path
>>
>>
>> class h_block(gr.hier_block2):
>>      def __init__(self):
>>          gr.hier_block2.__init__(self, "hello", gr.io_signature(0, 0, 0), 
>> gr.io_signature(0, 0, 0))
>>
>> class top_block(gr.top_block):
>>      def __init__(self, mod_class, demod_class, rx_callback, options):
>>          gr.top_block.__init__(self)
>>
>>          self.txpath = transmit_path(mod_class, options)
>>          self.rxpath = receive_path(demod_class, rx_callback, options)
>
> Try adding:
>
>           self.connect(self.txpath)
>           self.connect(self.rxpath)
>
> here.  See also tunnel.py
>
>
>>          self.source = gr.null_source(gr.sizeof_gr_complex)
>>          self.sink = gr.null_sink(gr.sizeof_gr_complex)
>>
>>
>>          self.connect(self.txpath, self.sink)
>>         # self.connect(self.source2, self.sink2)
>>
>>      def reconfigure(self):
>>          self.lock()
>>          self.disconnect(self.txpath, self.sink)
>>          self.sink2 = gr.null_sink(gr.sizeof_gr_complex)
>>          self.connect(self.txpath, self.sink2)
>>          self.unlock()
>
>
>
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