Allow duplex mode for PortAudio ALSA devices

cpp_src/device/portaudio/lasp_portaudiodaq.cpp

@@ -137,6 +137,9 @@ void fillPortAudioDeviceInfo(DeviceInfoList &devinfolist) {
       d.ninchannels = deviceInfo->maxInputChannels;
       d.noutchannels = deviceInfo->maxOutputChannels;
 
+      // Duplex mode, only for ALSA devices
+      d.hasDuplexMode = hasDuplexMode;
+
       devinfolist.push_back(std::make_unique<OurPaDeviceInfo>(d));
     }
   }
@@ -349,13 +352,6 @@ void PortAudioDaq::start(InDaqCallback inCallback, OutDaqCallback outCallback) {
     throw rte("Stream is already running");
   }
 
-  // Logical XOR
-  if (inCallback && outCallback) {
-    throw rte(
-        "Either input or output stream possible for PortAudio. "
-        "Stream duplex mode not provided.");
-  }
-
   if (neninchannels() > 0) {
     if (!inCallback) {
       throw rte(