--- a/support/mixer-qt4/ffado/panelmanager.py	2018-01-11 12:27:20.518923209 +0900
+++ a/support/mixer-qt4/ffado/panelmanager.py	2018-01-11 12:31:03.956299962 +0900
@@ -38,6 +38,7 @@
 
 import sys
 import time
+import importlib
 
 import logging
 log = logging.getLogger('panelmanager')
@@ -302,20 +303,15 @@
         #
         # Specific (or dummy) mixer widgets get loaded in the following
         #
+        found = False
         if 'mixer' in dev and dev['mixer'] != None:
             mixerapp = dev['mixer']
-            global mixerwidget
-            exec( """
-try:
-    import ffado.mixer.%s
-    globals()["mixerwidget"] = ffado.mixer.%s.%s( w )
-    found = True
-except ImportError:
-    log.debug("bypassdbus set, %s module not available: ignored")
-    found = False
-""" % (mixerapp.lower(), mixerapp.lower(), mixerapp, mixerapp.lower()) )
-        else:
-            found = False
+            try:
+                mixer_module = importlib.import_module("ffado.mixer.%s" % mixerapp.lower())
+                mixerwidget = getattr(mixer_module, mixerapp)(w)
+                found = True
+            except ImportError:
+                log.debug("bypassdbus set, %s module not available: ignored" % mixerapp.lower())
 
         if not found:
             mixerwidget = Dummy( w )
--- 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
@@ -194,7 +194,7 @@
         #log.debug("Got %i peaks" % len(peakvalues))
         for peak in peakvalues:
             #log.debug("peak = [%s,%s]" % (str(peak[0]),str(peak[1])))
-            if peak[0] >= 0:
+            if peak[1] >= 0:
                 self.switchers[peak[0]].peakValue(peak[1])
 
     def updateMixerRouting(self):
--- a/support/mixer-qt4/ffado/widgets/matrixmixer.py	2018-01-11 12:54:27.545361864 +0900
+++ b/support/mixer-qt4/ffado/widgets/matrixmixer.py	2018-01-11 12:56:36.899124318 +0900
@@ -512,7 +512,7 @@
                     self.rowHeaders[j].lbl.setText(row_name)
 
     def updateValues(self, n):
-        nbitems = len(n)/3
+        nbitems = len(n) // 3
         for i in range(nbitems):
             n_0 = n[3*i]    
             n_1 = n[3*i+1]   
@@ -951,7 +951,7 @@
             return self.interface.setValue(In, Out, val)            
 
     def updateValues(self, n):
-        nbitems = len(n)/3
+        nbitems = len(n) // 3
         for j in range(nbitems):
             n_0 = n[3*j]    
             n_1 = n[3*j+1]   
@@ -1406,7 +1406,7 @@
     def matrixControlChanged(self, n):
         # Update value needed for "per Out" view
         #log.debug("Update per Output( %s )" % str(n))
-        nbitems = len(n)/3
+        nbitems = len(n) // 3
         if (self.rule == "Columns_are_inputs"):
            n_t = n
         else:
@@ -1420,7 +1420,7 @@
     def sliderControlChanged(self, n):
         # Update value needed for matrix view
         #log.debug("Update Matrix( %s )" % str(n))
-        nbitems = len(n)/3
+        nbitems = len(n) // 3
         if (((self.rule == "Columns_are_inputs") and not self.transpose) or ((self.rule != "Columns_are_inputs") and self.transpose)):
             n_t = ()
             for i in range(nbitems):
@@ -1512,7 +1512,7 @@
                 log.debug("Number of stereo output channels must be specified")
                 return False
             n = int(readMixerString[idx+2])
-            if n > self.perOut.nbOut/2:
+            if n > self.perOut.nbOut // 2:
                 log.debug("Incoherent number of stereo channels")
                 return False
             if n > 0: