Ensure that the previous HID reports in the HID device class driver are kept per-instance, rather than per-device.

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

@@ -150,8 +150,6 @@ bool HID_Device_ConfigureEndpoints(USB_ClassInfo_HID_Device_t* const HIDInterfac
 		
 void HID_Device_USBTask(USB_ClassInfo_HID_Device_t* const HIDInterfaceInfo)
 {
-	static uint8_t PreviousReportINData[HID_MAX_REPORT_SIZE];
-
 	if (USB_DeviceState != DEVICE_STATE_Configured)
 	  return;
 
@@ -167,10 +165,10 @@ void HID_Device_USBTask(USB_ClassInfo_HID_Device_t* const HIDInterfaceInfo)
 
 		ReportINSize  = CALLBACK_HID_Device_CreateHIDReport(HIDInterfaceInfo, &ReportID, ReportINData);
 
-		bool StatesChanged     = (memcmp(ReportINData, PreviousReportINData, ReportINSize) != 0);
+		bool StatesChanged     = (memcmp(ReportINData, HIDInterfaceInfo->State.PreviousReportINData, ReportINSize) != 0);
 		bool IdlePeriodElapsed = (HIDInterfaceInfo->State.IdleCount && !(HIDInterfaceInfo->State.IdleMSRemaining));
 		
-		memcpy(PreviousReportINData, ReportINData, ReportINSize);
+		memcpy(HIDInterfaceInfo->State.PreviousReportINData, ReportINData, ReportINSize);
 
 		if (ReportINSize && (StatesChanged || IdlePeriodElapsed))
 		{

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

@@ -88,7 +88,9 @@
 					bool     UsingReportProtocol; /**< Indicates if the HID interface is set to Boot or Report protocol mode */
 					uint16_t IdleCount; /**< Report idle period, in mS, set by the host */
 					uint16_t IdleMSRemaining; /**< Total number of mS remaining before the idle period elapsed - this should be
-											   *   decremented by the user application if non-zero each millisecond */			
+											   *   decremented by the user application if non-zero each millisecond */	
+
+					uint8_t PreviousReportINData[HID_MAX_REPORT_SIZE]; /**< Previously generated report from the HID interface */
 				} State; /**< State data for the USB class interface within the device. All elements in this section
 				          *   are reset to their defaults when the interface is enumerated.
 				          */