--- a/dom/media/webrtc/MediaEngineWebRTCAudio.cpp
+++ b/dom/media/webrtc/MediaEngineWebRTCAudio.cpp
@@ -461,16 +461,17 @@ MediaEngineWebRTCMicrophoneSource::Updat
         uint32_t channelCount = 0;
         mAudioInput->GetChannelCount(channelCount);
         MOZ_ASSERT(channelCount > 0);
         prefs.mChannels = channelCount;
       }
       break;
 
     case kStarted:
+    case kStopped:
       if (prefs == mLastPrefs) {
         return NS_OK;
       }
 
       if (prefs.mChannels != mLastPrefs.mChannels) {
         // If the channel count changed, tell the MSG to open a new driver with
         // the correct channel count.
         MOZ_ASSERT(!mAllocations.IsEmpty());