mg: Temporarily disable concurrency in parts of set_rpc_client()

There is an issue with parallel inits and liberio which crops up during
initialization. This is not a fix but is a workaround which enables the
parallel initialization of devices using liberio.

2 files changed, 15 insertions, 1 deletions

diff --git a/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.cpp b/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.cpp
index 1c6a1733f..ebb350f4a 100644
--- a/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.cpp
+++ b/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.cpp
@@ -853,6 +853,8 @@ std::string magnesium_radio_ctrl_impl::get_dboard_fe_from_chan(
     return std::to_string(chan);
 }
 
+std::mutex magnesium_radio_ctrl_impl::_set_rpc_lock; // FIXME remove
+
 void magnesium_radio_ctrl_impl::set_rpc_client(
     uhd::rpc_client::sptr rpcc,
     const uhd::device_addr_t &block_args
@@ -897,7 +899,15 @@ void magnesium_radio_ctrl_impl::set_rpc_client(
     }
     UHD_LOG_DEBUG(unique_id(),
         "Master Clock Rate is: " << (_master_clock_rate / 1e6) << " MHz.");
-    radio_ctrl_impl::set_rate(_master_clock_rate);
+    {
+        // FIXME: Remove this lock. It's masking a bug that's probably, but not
+        // confirmed, to be in the receive packet demuxer. It'll pop up when
+        // running UHD over liberio without using serialize_init
+        std::lock_guard<std::mutex> l(magnesium_radio_ctrl_impl::_set_rpc_lock);
+        radio_ctrl_impl::set_rate(_master_clock_rate);
+        // Note: This lock needs to encompass all CHDR traffic. RPC traffic is
+        // OK from a thread-safety perspective.
+    }
 
     // EEPROM paths subject to change FIXME
     const size_t db_idx = get_block_id().get_block_count();
diff --git a/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.hpp b/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.hpp
index d12666ce7..e3cfe03e3 100644
--- a/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.hpp
+++ b/host/lib/usrp/dboard/magnesium/magnesium_radio_ctrl_impl.hpp
@@ -142,6 +142,10 @@ public:
     size_t get_chan_from_dboard_fe(const std::string &fe, const direction_t dir);
     std::string get_dboard_fe_from_chan(const size_t chan, const direction_t dir);
 
+    //! Disable concurrency in set_rpc_client(). This is a workaround for a
+    // thread-unsafety bug and should get deleted at some point in the future!
+    static std::mutex _set_rpc_lock; // FIXME remove this
+
     void set_rpc_client(
         uhd::rpc_client::sptr rpcc,
         const uhd::device_addr_t &block_args