--- a/support/mixer-qt4/ffado/widgets/crossbarrouter.py	2018-01-11 12:34:10.200777889 +0900
+++ b/support/mixer-qt4/ffado/widgets/crossbarrouter.py	2018-01-11 12:45:13.278911705 +0900
@@ -98,7 +98,7 @@
             self.combo.setCurrentIndex(self.combo.findText(src))
         else:
             self.combo.setCurrentIndex(0)
-        self.combo.activated.connect(self.comboCurrentChanged)
+        self.combo.activated[str].connect(self.comboCurrentChanged)
 
 
     def peakValue(self, value):