Fixed broken MIDI host driver MIDI_Host_ReceiveEventPacket() function due to not unfreezing the MIDI data IN pipe before use (thanks to Michael Brown).

LUFA/DoxygenPages/ChangeLog.txt

@@ -56,6 +56,7 @@
   *   - Fixed inverted LED logic in the USB2AX board LED driver
   *   - Fixed possible deadlock in the CDC device driver if the USB connection is dropped while the CDC_REQ_SetLineEncoding control request is being processed by
   *     the stack (thanks to Jonathan Hudgins)
+  *   - Fixed broken MIDI host driver MIDI_Host_ReceiveEventPacket() function due to not unfreezing the MIDI data IN pipe before use (thanks to Michael Brown)
   *  - Library Applications:
   *   - Fixed error in the AVRISP-MKII programmer when ISP mode is used at 64KHz (thanks to Ben R. Porter)
   *   - Fixed AVRISP-MKII programmer project failing to compile for the U4 chips when VTARGET_ADC_CHANNEL is defined to an invalid channel and NO_VTARGET_DETECT is

LUFA/Drivers/USB/Class/Host/MIDIClassHost.c

@@ -192,18 +192,27 @@ bool MIDI_Host_ReceiveEventPacket(USB_ClassInfo_MIDI_Host_t* const MIDIInterface
 {
 	if ((USB_HostState != HOST_STATE_Configured) || !(MIDIInterfaceInfo->State.IsActive))
 	  return HOST_SENDCONTROL_DeviceDisconnected;
+	  
+	bool DataReady = false;
 
 	Pipe_SelectPipe(MIDIInterfaceInfo->Config.DataINPipe.Address);
+	Pipe_Unfreeze();
 
-	if (!(Pipe_IsReadWriteAllowed()))
-	  return false;
-
-	Pipe_Read_Stream_LE(Event, sizeof(MIDI_EventPacket_t), NULL);
-
-	if (!(Pipe_IsReadWriteAllowed()))
-	  Pipe_ClearIN();
+	if (Pipe_IsINReceived())
+	{
+		if (Pipe_BytesInPipe())
+		{
+			Pipe_Read_Stream_LE(Event, sizeof(MIDI_EventPacket_t), NULL);
+			DataReady = true;
+		}
 
-	return true;
+		if (!(Pipe_BytesInPipe()))
+		  Pipe_ClearIN();
+	}
+	
+	Pipe_Freeze();
+	
+	return DataReady;
 }
 
 #endif