Index: /branches/libffado-2.0/support/mixer-qt4/ffado_configuration.py
===================================================================
--- /branches/libffado-2.0/support/mixer-qt4/ffado_configuration.py (revision 1577)
+++ /branches/libffado-2.0/support/mixer-qt4/ffado_configuration.py (revision 1582)
@@ -35,9 +35,11 @@
 			self.updateFromFile( filename )
 
-	def updateFromFile( self, filename ):
+	def updateFromFile( self, filename, must_exist=False ):
 		filename = os.path.expanduser(filename)
 		log.debug("DeviceList::updateFromFile(%s)" % filename)
 		if not os.path.exists( filename ):
-			log.error("cannot open file")
+			if must_exist:
+				log.error("cannot open file")
+			return
 		f = open( filename, "r" )