Additional fixes to the MIDI host driver due to not unfreezing/re-freezing pipes correctly (thanks to Michael Brown).

Demos/Host/LowLevel/MIDIHost/MIDIHost.c

@@ -167,6 +167,7 @@ void MIDIHost_Task(void)
 	  return;
 
 	Pipe_SelectPipe(MIDI_DATA_IN_PIPE);
+	Pipe_Unfreeze();
 
 	if (Pipe_IsINReceived())
 	{
@@ -188,7 +189,10 @@ void MIDIHost_Task(void)
 		}
 	}
 	
+	Pipe_Freeze();
+
 	Pipe_SelectPipe(MIDI_DATA_OUT_PIPE);
+	Pipe_Unfreeze();
 
 	if (Pipe_IsOUTReady())
 	{
@@ -251,6 +255,8 @@ void MIDIHost_Task(void)
 			Pipe_ClearOUT();
 		}
 
+		Pipe_Freeze();
+
 		/* Save previous joystick value for next joystick change detection */
 		PrevJoystickStatus = JoystickStatus;
 	}

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

@@ -156,14 +156,20 @@ uint8_t MIDI_Host_Flush(USB_ClassInfo_MIDI_Host_t* const MIDIInterfaceInfo)
 	uint8_t ErrorCode;
 
 	Pipe_SelectPipe(MIDIInterfaceInfo->Config.DataOUTPipe.Address);
+	Pipe_Unfreeze();
 	
 	if (Pipe_BytesInPipe())
 	{
 		Pipe_ClearOUT();
 
 		if ((ErrorCode = Pipe_WaitUntilReady()) != PIPE_READYWAIT_NoError)
+		{
+			Pipe_Freeze();
 			return ErrorCode;
 		}
+	}
+
+	Pipe_Freeze();
 
 	return PIPE_READYWAIT_NoError;
 }
@@ -177,13 +183,19 @@ uint8_t MIDI_Host_SendEventPacket(USB_ClassInfo_MIDI_Host_t* const MIDIInterface
 	uint8_t ErrorCode;
 
 	Pipe_SelectPipe(MIDIInterfaceInfo->Config.DataOUTPipe.Address);
+	Pipe_Unfreeze();
 	
 	if ((ErrorCode = Pipe_Write_Stream_LE(Event, sizeof(MIDI_EventPacket_t), NULL)) != PIPE_RWSTREAM_NoError)
+	{
+		Pipe_Freeze();
 		return ErrorCode;
+	}
 
 	if (!(Pipe_IsReadWriteAllowed()))
 	  Pipe_ClearOUT();
 
+	Pipe_Freeze();
+
 	return PIPE_RWSTREAM_NoError;
 }