diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index c40180e91d..3453deea5c 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -1166,16 +1166,22 @@ AudioEngine::get_physical (DataType type, unsigned long flags, vector<string>& p
 	}
 }
 
+/** Get physical ports for which JackPortIsOutput is set; ie those that correspond to
+ *  a physical input connector.
+ */
 void
 AudioEngine::get_physical_inputs (DataType type, vector<string>& ins)
 {
-	get_physical (type, JackPortIsInput, ins);
+	get_physical (type, JackPortIsOutput, ins);
 }
 
+/** Get physical ports for which JackPortIsInput is set; ie those that correspond to
+ *  a physical output connector.
+ */
 void
 AudioEngine::get_physical_outputs (DataType type, vector<string>& outs)
 {
-	get_physical (type, JackPortIsOutput, outs);
+	get_physical (type, JackPortIsInput, outs);
 }
 
 void
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 6e557e6d49..7978123695 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -431,11 +431,8 @@ Session::when_engine_running ()
 	vector<string> inputs[DataType::num_types];
 	vector<string> outputs[DataType::num_types];
 	for (uint32_t i = 0; i < DataType::num_types; ++i) {
-		/* the engine's terms for inputs and outputs are reversed from what the
-		   code below expects.
-		 */
-		_engine.get_physical_outputs (DataType (DataType::Symbol (i)), inputs[i]);
-		_engine.get_physical_inputs (DataType (DataType::Symbol (i)), outputs[i]);
+		_engine.get_physical_inputs (DataType (DataType::Symbol (i)), inputs[i]);
+		_engine.get_physical_outputs (DataType (DataType::Symbol (i)), outputs[i]);
 	}
 
 	/* Create a set of Bundle objects that map