I’m just getting started with grc but I am having problems already.
I have a simple flow graph: an audio source with a device name “hw:1,0”
connected to a WX scope sink.
hw:1,0 is my Logitech headset according to ‘arecord -l’.
The first time i run my flow graph after booting up, it works fine.
After stoping
the flow graph, any subsequent time I try to run it, I get an error. I
can only
clear the error by rebooting. Simply restarting grc is not enough.
My ‘uname -u’ output is:
Linux zbox 3.2.0-4-amd64 #1 SMP Debian 3.2.63-2+deb7u2 x86_64 GNU/Linux
and i built my gnuradio with build-gnuradio a few days ago.
Here is the grc output:
tom@zbox:~$ gnuradio-companion
linux; GNU C++ version 4.7.2; Boost_104900; UHD_003.008.000-52-g2068af70
<<< Welcome to GNU Radio Companion 3.7.5.1 >>>
Preferences file: /home/tom/.grc
Block paths:
/usr/local/share/gnuradio/grc/blocks
/home/tom/.grc_gnuradio
Loading: “/home/tom/grc/playing.grc”
Done
Showing: “/home/tom/grc/playing.grc”
Loading: “/home/tom/dialtone.grc”
Done
Generating: “/home/tom/grc/top_block.py”
Executing: “/home/tom/grc/top_block.py”
Using Volk machine: avx_64_mmx_orc
INFO: Audio source arch: alsa
Done
Generating: “/home/tom/grc/top_block.py”
Executing: “/home/tom/grc/top_block.py”
Using Volk machine: avx_64_mmx_orc
INFO: Audio source arch: alsa
ERROR: [hw:1,0]: snd_pcm_hw_params failed: Input/output error
Traceback (most recent call last):
File “/home/tom/grc/top_block.py”, line 76, in
tb.Start(True)
File “/usr/local/lib/python2.7/dist-
packages/grc_gnuradio/wxgui/top_block_gui.py”, line 73, in Start
self.start()
File
“/usr/local/lib/python2.7/dist-packages/gnuradio/gr/top_block.py”, line
104, in start
top_block_start_unlocked(self._tb, max_noutput_items)
File
“/usr/local/lib/python2.7/dist-packages/gnuradio/gr/runtime_swig.py”,
line 4724, in top_block_start_unlocked
return _runtime_swig.top_block_start_unlocked(*args, **kwargs)
RuntimeError: check topology failed on audio_alsa_source(8) using
ninputs=0,
noutputs=1
Done