HRESULT XDisplayAcquireTimeoutDeferral(  
         XDisplayTimeoutDeferralHandle* handle  
)  

void Game::PlayIntroCutscene()
{
    XDisplayTimeoutDeferralHandle handle;

    // Try to acquire a new timeout deferral handle.
    if (SUCCEEDED(XDisplayAcquireTimeoutDeferral(&handle)))
    {
        // The newly-opened timeout deferral handle prevents the display
        // from dimming over the game if the user goes idle.
        // 
        // At this point, the long intro cutscene can play without dimmming.
    }

    // Once the cutscene has completed playing, 
    // close the timeout deferral handle.
    XDisplayCloseTimeoutDeferralHandle(handle);

    // If there are no open timeout deferral handles, the display can
    // once again dim over the game if the user goes idle.
}