usrp2: stop streaming and drain buffer (if left running)

2 files changed, 11 insertions, 4 deletions

diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index aa6d15783..9e29edd82 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -144,11 +144,13 @@ void usrp2_impl::io_impl::recv_pirate_loop(
  **********************************************************************/
 void usrp2_impl::io_init(void){
     //send a small data packet so the usrp2 knows the udp source port
-    for(size_t i = 0; i < _data_transports.size(); i++){
-        managed_send_buffer::sptr send_buff = _data_transports[i]->get_send_buff();
-        boost::uint32_t data = htonl(USRP2_INVALID_VRT_HEADER);
-        memcpy(send_buff->cast<void*>(), &data, sizeof(data));
+    BOOST_FOREACH(zero_copy_if::sptr data_transport, _data_transports){
+        managed_send_buffer::sptr send_buff = data_transport->get_send_buff();
+        static const boost::uint32_t data = htonl(USRP2_INVALID_VRT_HEADER);
+        std::memcpy(send_buff->cast<void*>(), &data, sizeof(data));
         send_buff->commit(sizeof(data));
+        //drain the recv buffers (may have junk)
+        while (data_transport->get_recv_buff().get());
     }
 
     //the number of recv frames is the number for the first transport
diff --git a/host/lib/usrp/usrp2/mboard_impl.cpp b/host/lib/usrp/usrp2/mboard_impl.cpp
index 0ac988361..3d103c940 100644
--- a/host/lib/usrp/usrp2/mboard_impl.cpp
+++ b/host/lib/usrp/usrp2/mboard_impl.cpp
@@ -98,6 +98,11 @@ usrp2_mboard_impl::usrp2_mboard_impl(
 
     //init the tx and rx dboards (do last)
     dboard_init();
+
+    //Issue a stop streaming command (in case it was left running).
+    //Since this command is issued before the networking is setup,
+    //most if not all junk packets will never make it to the socket.
+    this->issue_ddc_stream_cmd(stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS);
 }
 
 usrp2_mboard_impl::~usrp2_mboard_impl(void){