3 files changed, 69 insertions, 1 deletions
diff --git a/host/lib/include/uhdlib/transport/link_if.hpp b/host/lib/include/uhdlib/transport/link_if.hpp
index 6f533603e..55755948c 100644
--- a/host/lib/include/uhdlib/transport/link_if.hpp
+++ b/host/lib/include/uhdlib/transport/link_if.hpp
@@ -57,6 +57,15 @@ public:
      */
     virtual adapter_id_t get_send_adapter_id() const = 0;
 
+    /*!
+     * Returns whether this link type supports releasing the frame buffers
+     * in an order different from that in which they were acquired.
+     */
+    virtual bool supports_send_buff_out_of_order() const
+    {
+        return true;
+    }
+
     send_link_if()                    = default;
     send_link_if(const send_link_if&) = delete;
     send_link_if& operator=(const send_link_if&) = delete;
@@ -102,6 +111,15 @@ public:
      */
     virtual adapter_id_t get_recv_adapter_id() const = 0;
 
+    /*!
+     * Returns whether this link type supports releasing the frame buffers
+     * in an order different from that in which they were acquired.
+     */
+    virtual bool supports_recv_buff_out_of_order() const
+    {
+        return true;
+    }
+
     recv_link_if()                    = default;
     recv_link_if(const recv_link_if&) = delete;
     recv_link_if& operator=(const recv_link_if&) = delete;
diff --git a/host/lib/include/uhdlib/transport/nirio_link.hpp b/host/lib/include/uhdlib/transport/nirio_link.hpp
index 055874146..2335e311c 100644
--- a/host/lib/include/uhdlib/transport/nirio_link.hpp
+++ b/host/lib/include/uhdlib/transport/nirio_link.hpp
@@ -104,6 +104,24 @@ public:
         return _adapter_id;
     }
 
+    /*!
+     * Returns whether this link type supports releasing the frame buffers
+     * in an order different from that in which they were acquired.
+     */
+    bool supports_send_buff_out_of_order() const
+    {
+        return false;
+    }
+
+    /*!
+     * Returns whether this link type supports releasing the frame buffers
+     * in an order different from that in which they were acquired.
+     */
+    bool supports_recv_buff_out_of_order() const
+    {
+        return false;
+    }
+
 private:
     using recv_link_base_t = recv_link_base<nirio_link>;
     using send_link_base_t = send_link_base<nirio_link>;
diff --git a/host/lib/usrp/common/io_service_mgr.cpp b/host/lib/usrp/common/io_service_mgr.cpp
index c00f36a25..437d77423 100644
--- a/host/lib/usrp/common/io_service_mgr.cpp
+++ b/host/lib/usrp/common/io_service_mgr.cpp
@@ -435,6 +435,9 @@ private:
     };
     using link_pair_t = std::pair<recv_link_if::sptr, send_link_if::sptr>;
 
+    bool _out_of_order_supported(
+        recv_link_if::sptr recv_link, send_link_if::sptr send_link) const;
+
     const uhd::device_addr_t _args;
 
     inline_io_service_mgr _inline_io_srv_mgr;
@@ -453,12 +456,19 @@ io_service_mgr::sptr io_service_mgr::make(const uhd::device_addr_t& args)
 io_service::sptr io_service_mgr_impl::connect_links(recv_link_if::sptr recv_link,
     send_link_if::sptr send_link,
     const link_type_t link_type,
-    const io_service_args_t& default_args,
+    const io_service_args_t& default_args_,
     const uhd::device_addr_t& stream_args,
     const std::string& streamer_id)
 {
     UHD_ASSERT_THROW(link_type != link_type_t::ASYNC_MSG);
 
+    io_service_args_t default_args = default_args_;
+
+    if (!_out_of_order_supported(recv_link, send_link)) {
+        default_args.recv_offload = false;
+        default_args.send_offload = false;
+    }
+
     const io_service_args_t args = read_io_service_args(
         merge_io_service_dev_args(_args, stream_args), default_args);
 
@@ -498,6 +508,15 @@ io_service::sptr io_service_mgr_impl::connect_links(recv_link_if::sptr recv_link
         }
     }
 
+    // If the link doesn't support buffers out of order, then we can only use
+    // the inline I/O service. Warn if a different one was requested.
+    if (!_out_of_order_supported(recv_link, send_link)) {
+        if (io_srv_type != INLINE_IO_SRV) {
+            UHD_LOG_WARNING(LOG_ID, "Link type does not support send/recv offload, ignoring");
+        }
+        io_srv_type = INLINE_IO_SRV;
+    }
+
     switch (io_srv_type) {
         case INLINE_IO_SRV:
             io_srv = _inline_io_srv_mgr.connect_links(recv_link, send_link);
@@ -541,4 +560,17 @@ void io_service_mgr_impl::disconnect_links(
     _link_info_map.erase(it);
 }
 
+bool io_service_mgr_impl::_out_of_order_supported(
+    recv_link_if::sptr recv_link, send_link_if::sptr send_link) const
+{
+    bool supported = true;
+    if (recv_link) {
+        supported = recv_link->supports_recv_buff_out_of_order();
+    }
+    if (send_link) {
+        supported = supported && send_link->supports_send_buff_out_of_order();
+    }
+    return supported;
+}
+
 }} // namespace uhd::usrp