fix AU bus sidechaining

diff --git a/libs/ardour/audio_unit.cc b/libs/ardour/audio_unit.cc
index d276320d336da6afdc8b591939cb5f0cecc4fad7..74e0cc280036fffde6c6f9e6007d53c8d6917b9b 100644 (file)
--- a/libs/ardour/audio_unit.cc
+++ b/libs/ardour/audio_unit.cc
@@ -1267,9 +1267,10 @@ AUPlugin::can_support_io_configuration (const ChanCount& in, ChanCount& out, Cha
                                continue;
                        }
                        for (uint32_t i = 1; i < input_elements; ++i) {
-                               for (uint32_t j = 0; j < bus_inputs[i]; ++j) {
-                                       io_configs.push_back (pair<int,int> (possible_in + j, possible_out));
-                               }
+                               // can't use up-to bus_inputs[]
+                               // waves' SC-C6(s) for example fails to configure with only 1 input
+                               // on the 2nd bus.
+                               io_configs.push_back (pair<int,int> (possible_in + bus_inputs[i], possible_out));
                        }
                }
        }