Not Receiving USB_EVENT_CONNECTED events in USB OTG Host with TM4C1294KCPDT

I am converting an existing Stellaris product into one using the TM4C1294KCPDT chip.  The USB OTG Device side works correctly, but the Host side does not.

I have traced the problem to the events being sent to my USBHCDEvents function -- it is receiving USB_EVENT_DISCONNECTED events every two seconds when a gamepad-like device is attached but it never receives a USB_EVENT_CONNECTED event.  (The OTG polling is set for two seconds.)

My USB_OTGModeCallback function, which is called from the TIVAWARE at an interrupt level, does report that it is oscillating between the eUSBModeHost and the eUSBModeNone modes at the two second rate.  

I also notice that my USBHHandpadCallback never seems to be called.  Is suspect this is a consequence of the never fulling connecting....

Suggestions?

Tom

Code bit 1:

// Declare the USB Events driver interface.
DECLARE_EVENT_DRIVER(g_sUSBEventDriver, 0, 0, USBHCDEvents);
void USBHCDEvents(void *pvData);

// The global that holds all of the host drivers in use in the application.
// Two class drivers are supported -- HID and USBEvents
static const tUSBHostClassDriver * const g_ppHostClassDrivers[] =
{
        &g_sUSBHIDClassDriver,
        &g_sUSBEventDriver
};

// This global holds the number of class drivers in the g_ppHostClassDrivers list.
static const uint32_t g_ui32NumHostClassDrivers =
    sizeof(g_ppHostClassDrivers) / sizeof(tUSBHostClassDriver *);

Code bit 2:

//*****************************************************************************
//
// USB initialization
//
// Hint:  Unlike the rest of usb.c, this function runs prior to starting
//            multi-tasking.
//
//*****************************************************************************
void USB_USBOTGinit(void)
{
    uint32_t ui32PLLFreqHz;
    bool bResult;
    Error_Block eb;

    //------------------------------------------------------------------------------------------------------
    //    Set up the chip hardware
    //------------------------------------------------------------------------------------------------------

    // Enable the USB peripheral and PLL (if required)
    SysCtlPeripheralEnable(SYSCTL_PERIPH_USB0);
    // SysCtlUSBPLLEnable(); // Required for TM4C123, must not be present for TM4C129.....

    // Tell the USB library the PLL frequency
    ui32PLLFreqHz = 480000000;
    bResult = USBOTGFeatureSet(0, USBLIB_FEATURE_USBPLL, &ui32PLLFreqHz);
    if (!bResult)
    {
        System_printf("USBLIB_FEATURE_USBPLL failed!\n");
        System_flush();
    }

    // Setup USB host power control signal pins
    // (Hint:  USB TIVAWARE manual states other pins are handled by OTG init See Section 4.2.1)
    GPIOPinConfigure(GPIO_PA6_USB0EPEN);
    GPIOPinConfigure(GPIO_PA7_USB0PFLT);
    GPIOPinTypeUSBDigital(NEWP_GPIO_PORTA_BASE, GPIO_PIN_6 | GPIO_PIN_7);
    USBHCDPowerConfigInit(0, USBHCD_FAULT_LOW | USBHCD_FAULT_VBUS_DIS | USBHCD_VBUS_FILTER | USBHCD_VBUS_AUTO_HIGH);

    // Setup VBUS, ID, D+ and D- pins for USB operation
    GPIOPinTypeUSBAnalog(NEWP_GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    GPIOPinTypeUSBAnalog(NEWP_GPIO_PORTL_BASE, GPIO_PIN_6 | GPIO_PIN_7);

    //------------------------------------------------------------------------------------------------------
    //    Initialize the USB OTG state
    //------------------------------------------------------------------------------------------------------
    USBStackModeSet(0, eUSBModeOTG, USB_OTGModeCallback); // set up the stack and OTG mode change callback function
    g_eUSBState = STATE_NO_DEVICE;  // Indicate, initially, that we are waiting for a device to be connected
    g_eUSBDeviceState = DEVICE_STATE_NOT_CONFIGURED;  // Indicate, initially, that we are not configured

    //------------------------------------------------------------------------------------------------------
    //    Initialize the device stacks
    //------------------------------------------------------------------------------------------------------
    //
    // Initialize the transmit and receive buffers.
    //
    USBBufferInit(&g_sTxBuffer);
    USBBufferInit(&g_sRxBuffer);

    // Only Bulk Transfer type of device is supported
    USBDBulkInit(0, &g_sBulkDevice);

    //------------------------------------------------------------------------------------------------------
    //    Initialize the host stacks
    //------------------------------------------------------------------------------------------------------
    // Register the host class drivers.
    USBHCDRegisterDrivers(0, g_ppHostClassDrivers, g_ui32NumHostClassDrivers);  // Hint: only driver registered is HID

     // Initialize the handpad driver.  As part of that process, open an instance of the handpad driver.
    USBHHandpadOpen(pui8InBuffer, pui8OutBuffer);

    // Initialize the host control stack
    USBHCDInit(0, g_pui8HCDPool, HCD_MEMORY_SIZE);

    //------------------------------------------------------------------------------------------------------
    //    Set up the HAL to deal with USBOTG interrupts
    //------------------------------------------------------------------------------------------------------
    Error_init(&eb);

    Hwi_Params_init(&USBOTG_Hwi_Params);
    USBOTG_Hwi_Params.priority = USB0_Priority;
    USBOTG_Hwi_Params.enableInt = true;

    USBOTG_Hwi_Handle = Hwi_create(INT_USB0, USB0OTGModeIntHandler_wrapper, &USBOTG_Hwi_Params, &eb);
    if (NULL == USBOTG_Hwi_Handle)
    {
        System_abort("USBOTG Hwi create failed");
    }

    //------------------------------------------------------------------------------------------------------
    //    Initialize and Enable the USB controller
    //------------------------------------------------------------------------------------------------------
    // Initialize the loop timer reference time
    ui32LastPassTicks = Clock_getTicks();

    // Initialize and Enable the USB controller
    USBOTGModeInit(0, ui32MillisecToTicks(0, USBOTG_POLLING_RATE_MS), g_pui8HCDPool, HCD_MEMORY_SIZE);

Code bit 3 (from my handpad driver file):
void
USBHHandpadOpen(uint8_t *pui8InBuffer, uint8_t *pui8OutBuffer)
{
   // Save the callback and data pointers.
    g_sUSBHHandpad.pfnCallback = USBHHandpadCallback;

    // Save the instance pointer for the HID device that was opened.
    g_sUSBHHandpad.psHIDInstance = USBHHIDOpen(eUSBHHIDClassVendor, USBHHandpadCallback, (void *)&g_sUSBHHandpad);

    // Save the buffer memory locations and the buffer size
    g_sUSBHHandpad.pui8InBuffer = pui8InBuffer;
    g_sUSBHHandpad.pui8OutBuffer = pui8OutBuffer;
    g_sUSBHHandpad.ui32HIDFlags = ~USBHHANDPAD_DEVICE_PRESENT; // Initialize with device not connected
}

.