Err, weirdly I thought I had updated this commit to remove the comment; lemme do that and resend.

-a

On Mon, 9 Nov 2020 at 10:03, Adrian Chadd adrian@freebsd.org wrote:

Fix receive path hangs if another thread closes down the hackrf receive whilst this buffer receive function is waiting to be woken up.

Now:

• Sleep for up to 100ms each time waiting for the cond to be kicked;
• Check whether streaming is still enabled each time rather than only when the function is entered.

This fixes hangs where consumers like gqrx via gnuradio will do a stop_rx/start_rx very quickly to change something, and the buffer receive path is waiting for a buffer.

---

lib/hackrf/hackrf_source_c.cc | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/lib/hackrf/hackrf_source_c.cc b/lib/hackrf/hackrf_source_c.cc index 662d04a..21656f9 100644 --- a/lib/hackrf/hackrf_source_c.cc +++ b/lib/hackrf/hackrf_source_c.cc @@ -30,6 +30,7 @@

#include <stdexcept> #include <iostream> +#include <chrono>

#include <gnuradio/io_signature.h>

@@ -203,8 +204,22 @@ int hackrf_source_c::work( int noutput_items, { std::unique_lockstd::mutex lock(_buf_mutex);

• while (_buf_used < 3 && running) // collect at least 3 buffers

•  _buf_cond.wait( lock );
  

• // XXX adrian - tomorrow, turn this loop into a wait_for (1 second)

• // and re-check dev.get / running !

• // Otherwise this will hang reasonably reliably if we race where

• // receive is stopped in one thread, and we've already passed

• // the hackrf_is_streaming() check; we'll never finish this loop

• // and consumers (eg gqrx) will fail.

• while (_buf_used < 3 && running) { // collect at least 3 buffers

•  _buf_cond.wait_for( lock , std::chrono::milliseconds(100));
  

•  // Re-check whether the device has closed or stopped streaming
  

•  if ( _dev.get() )
  

•    running = (hackrf_is_streaming( _dev.get() ) == HACKRF_TRUE);
  

•  else
  

•    running = false;
  

• } }

  if ( ! running )

-- 2.28.0