Audio_sink using unlock() crashes


I am having issues with lock()/unlock() when my flow graph contains an
audio_sink. Runs ok untill it locks() and unlocks() the flowgraph to
change parameters. I confirmed it is the audio_sink by replacing it with
a null_sink everything works fine.

Any ideas? Thanks

USRP2 using UHD
GNURadio 3.3.0
Ubuntu 10.04
Asus G51 Core I7 laptop

Traceback (most recent call last):
File “./”, line 127, in set_af_gain
line 1475, in unlock
return _gnuradio_swig_py_runtime.gr_top_block_sptr_unlock(self)
RuntimeError: check topology failed on audio_alsa_sink(23) using
ninputs=1, noutputs=0