Prevent the CDC Device Class driver from sending empty IN packets on every service task call - only send termination packets when data is in the endpoint.

LUFA/Doxygen.conf

@@ -1481,4 +1481,4 @@ DOT_CLEANUP            = YES
 # The SEARCHENGINE tag specifies whether or not a search engine should be 
 # used. If set to NO the values of all tags below this one will be ignored.
 
-SEARCHENGINE           = NO
+SEARCHENGINE           = YES

LUFA/Drivers/USB/Class/Device/CDC.c

@@ -143,11 +143,11 @@ uint8_t CDC_Device_SendByte(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo,
 	Endpoint_SelectEndpoint(CDCInterfaceInfo->Config.DataINEndpointNumber);
 
 	if (!(Endpoint_IsReadWriteAllowed()))
-	{
-		uint8_t ErrorCode;
-	
+	{	
 		Endpoint_ClearIN();
 
+		uint8_t ErrorCode;
+
 		if ((ErrorCode = Endpoint_WaitUntilReady()) != ENDPOINT_READYWAIT_NoError)
 		  return ErrorCode;
 	}
@@ -161,20 +161,26 @@ uint8_t CDC_Device_Flush(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo)
 	if ((USB_DeviceState != DEVICE_STATE_Configured) || !(CDCInterfaceInfo->State.LineEncoding.BaudRateBPS))
 	  return ENDPOINT_READYWAIT_NoError;
 
+	uint8_t ErrorCode;
+
 	Endpoint_SelectEndpoint(CDCInterfaceInfo->Config.DataINEndpointNumber);
+
+	if (!(Endpoint_BytesInEndpoint()))
+	  return ENDPOINT_READYWAIT_NoError;
+	
+	bool BankFull = !(Endpoint_IsReadWriteAllowed());
 	
-	if (Endpoint_BytesInEndpoint())
+	Endpoint_ClearIN();
+	
+	if (BankFull)
 	{
-		uint8_t ErrorCode;
-
-		Endpoint_ClearIN();
-		
 		if ((ErrorCode = Endpoint_WaitUntilReady()) != ENDPOINT_READYWAIT_NoError)
 		  return ErrorCode;
+
+		Endpoint_ClearIN();
 	}
 	
-	Endpoint_ClearIN();
-	return Endpoint_WaitUntilReady();
+	return ENDPOINT_READYWAIT_NoError;
 }
 
 uint16_t CDC_Device_BytesReceived(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo)

LUFA/Drivers/USB/Class/Device/CDC.h

@@ -192,10 +192,8 @@
 			/** Flushes any data waiting to be sent, ensuring that the send buffer is cleared.
 			 *
 			 *  \param[in,out] CDCInterfaceInfo  Pointer to a structure containing a CDC Class configuration and state.
-			 *
-			 *  \return A value from the \ref Endpoint_WaitUntilReady_ErrorCodes_t enum
 			 */
-			uint8_t CDC_Device_Flush(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1);
+			void CDC_Device_Flush(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo) ATTR_NON_NULL_PTR_ARG(1);
 			
 			/** Sends a Serial Control Line State Change notification to the host. This should be called when the virtual serial
 			 *  control lines (DCD, DSR, etc.) have changed states, or to give BREAK notfications to the host. Line states persist

LUFA/Drivers/USB/Class/Host/StillImage.h

@@ -181,7 +181,7 @@
 			/** Receives an asynchronous event block from the device via the asynchronous events pipe.
 			 *
 			 *  \param[in,out] SIInterfaceInfo  Pointer to a structure containing a Still Image Class host configuration and state
-			 *  \param[out] SI_PIMA_Container_t  Pointer to a PIMA container structure where the event should be stored
+			 *  \param[out] PIMAHeader  Pointer to a PIMA container structure where the event should be stored
 			 *
 			 *  \return A value from the \ref Pipe_Stream_RW_ErrorCodes_t enum, or \ref SI_ERROR_LOGICAL_CMD_FAILED if the device
 			 *          returned a logical command failure