3 files changed, 28 insertions, 10 deletions
diff --git a/host/lib/usrp/b200/b200_impl.cpp b/host/lib/usrp/b200/b200_impl.cpp
index 0da388b93..66ab813c2 100644
--- a/host/lib/usrp/b200/b200_impl.cpp
+++ b/host/lib/usrp/b200/b200_impl.cpp
@@ -252,7 +252,7 @@ b200_impl::b200_impl(const device_addr_t &device_addr)
     ////////////////////////////////////////////////////////////////////
     _async_task_data.reset(new AsyncTaskData());
     _async_task_data->async_md.reset(new async_md_type(1000/*messages deep*/));
-    _async_task = uhd::task::make(boost::bind(&b200_impl::handle_async_task, this, _ctrl_transport, _async_task_data));
+    _async_task = uhd::msg_task::make(boost::bind(&b200_impl::handle_async_task, this, _ctrl_transport, _async_task_data));
 
     ////////////////////////////////////////////////////////////////////
     // Local control endpoint
@@ -474,7 +474,7 @@ b200_impl::b200_impl(const device_addr_t &device_addr)
 
 b200_impl::~b200_impl(void)
 {
-    UHD_SAFE_CALL
+	UHD_SAFE_CALL
     (
         _async_task.reset();
     )
diff --git a/host/lib/usrp/b200/b200_impl.hpp b/host/lib/usrp/b200/b200_impl.hpp
index eced4a539..59a047e01 100644
--- a/host/lib/usrp/b200/b200_impl.hpp
+++ b/host/lib/usrp/b200/b200_impl.hpp
@@ -120,7 +120,7 @@ struct b200_impl : public uhd::device
     boost::weak_ptr<uhd::tx_streamer> _tx_streamer;
 
     //async ctrl + msgs
-    uhd::task::sptr _async_task;
+    uhd::msg_task::sptr _async_task;
     typedef uhd::transport::bounded_buffer<uhd::async_metadata_t> async_md_type;
     struct AsyncTaskData
     {
@@ -130,7 +130,7 @@ struct b200_impl : public uhd::device
         b200_uart::sptr gpsdo_uart;
     };
     boost::shared_ptr<AsyncTaskData> _async_task_data;
-    void handle_async_task(uhd::transport::zero_copy_if::sptr, boost::shared_ptr<AsyncTaskData>);
+    boost::optional<uhd::msg_task::msg_type_t> handle_async_task(uhd::transport::zero_copy_if::sptr, boost::shared_ptr<AsyncTaskData>);
 
     void register_loopback_self_test(uhd::wb_iface::sptr iface);
     void codec_loopback_self_test(uhd::wb_iface::sptr iface);
diff --git a/host/lib/usrp/b200/b200_io_impl.cpp b/host/lib/usrp/b200/b200_io_impl.cpp
index 1feeff1a3..7b09c87df 100644
--- a/host/lib/usrp/b200/b200_io_impl.cpp
+++ b/host/lib/usrp/b200/b200_io_impl.cpp
@@ -139,27 +139,44 @@ bool b200_impl::recv_async_msg(
     return _async_task_data->async_md->pop_with_timed_wait(async_metadata, timeout);
 }
 
-void b200_impl::handle_async_task(
+/*
+ * This method is constantly called in a msg_task loop.
+ * Incoming messages are dispatched in to the hosts radio_ctrl_cores.
+ * The radio_ctrl_core queues are accessed via a weak_ptr to them, stored in AsyncTaskData.
+ * During shutdown the radio_ctrl_core dtor's are called.
+ * An empty peek32(0) is sent out to flush pending async messages.
+ * The response to those messages can't be delivered to the ctrl_core queues anymore
+ * because the shared pointer corresponding to the weak_ptrs is no longer valid.
+ * Those stranded messages are put into a dump_queue implemented in msg_task.
+ * A radio_ctrl_core can search for missing messages there.
+ */
+boost::optional<uhd::msg_task::msg_type_t> b200_impl::handle_async_task(
     uhd::transport::zero_copy_if::sptr xport,
     boost::shared_ptr<AsyncTaskData> data
 )
 {
     managed_recv_buffer::sptr buff = xport->get_recv_buff();
-    if (not buff or buff->size() < 8) return;
+    if (not buff or buff->size() < 8)
+        return NULL;
+
     const boost::uint32_t sid = uhd::wtohx(buff->cast<const boost::uint32_t *>()[1]);
-    switch (sid)
-    {
+    switch (sid) {
 
     //if the packet is a control response
     case B200_RESP0_MSG_SID:
     case B200_RESP1_MSG_SID:
     case B200_LOCAL_RESP_SID:
     {
-        radio_ctrl_core_3000::sptr ctrl;
+    	radio_ctrl_core_3000::sptr ctrl;
         if (sid == B200_RESP0_MSG_SID) ctrl = data->radio_ctrl[0].lock();
         if (sid == B200_RESP1_MSG_SID) ctrl = data->radio_ctrl[1].lock();
         if (sid == B200_LOCAL_RESP_SID) ctrl = data->local_ctrl.lock();
-        if (ctrl) ctrl->push_response(buff->cast<const boost::uint32_t *>());
+        if (ctrl){
+        	ctrl->push_response(buff->cast<const boost::uint32_t *>());
+        }
+        else{
+            return std::make_pair(sid, uhd::msg_task::buff_to_vector(buff->cast<boost::uint8_t *>(), buff->size() ) );
+        }
         break;
     }
 
@@ -204,6 +221,7 @@ void b200_impl::handle_async_task(
     default:
         UHD_MSG(error) << "Got a ctrl packet with unknown SID " << sid << std::endl;
     }
+    return NULL;
 }
 
 /***********************************************************************