Consider the following scenario.
- You have a computer that is running Windows Vista or Windows Server 2008.
- You plug a USB video device into a USB root hub that has the USB selective suspend setting enabled.
- An application uses the USB device while the device is in selective suspend mode.
In this scenario, you may have to wait five seconds before the USB device starts to work. During this period, the application that uses the USB device appears unresponsive. For example, when you run an application to use a USB camera that is in selective suspend mode, you may have to wait five seconds for the video to appear in the application.
This problem typically occurs on computers that have multiple processors, multiple cores, or the hyper-threading feature.