GCS_MAVLink: scale parameter send rate according to link bandwidth

libraries/GCS_MAVLink/GCS_Param.cpp

@@ -53,11 +53,17 @@ GCS_MAVLINK::queued_param_send()
 
     // use at most 30% of bandwidth on parameters. The constant 26 is
     // 1/(1000 * 1/8 * 0.001 * 0.3)
-    bytes_allowed = 57 * (tnow - _queued_parameter_send_time_ms) * 26;
+    const uint32_t link_bw = _port->bw_in_kilobytes_per_second();
+
+    bytes_allowed = link_bw * (tnow - _queued_parameter_send_time_ms) * 26;
+    const uint16_t size_for_one_param_value_msg = MAVLINK_MSG_ID_PARAM_VALUE_LEN + packet_overhead();
+    if (bytes_allowed < size_for_one_param_value_msg) {
+        bytes_allowed = size_for_one_param_value_msg;
+    }
     if (bytes_allowed > comm_get_txspace(chan)) {
         bytes_allowed = comm_get_txspace(chan);
     }
-    count = bytes_allowed / (MAVLINK_MSG_ID_PARAM_VALUE_LEN + packet_overhead());
+    count = bytes_allowed / size_for_one_param_value_msg;
 
     // when we don't have flow control we really need to keep the
     // param download very slow, or it tends to stall