In Windows 7, Power Options->USB Settings->USB selective suspend setting, what does "USB selective suspend" mean? Also, given that there is only one setting, why does it say "USB Settings" instead of "USB Setting"?
A USB device driver can send a message to windows telling it to idle the device. This puts the device in a low-power state (the suspend state). When a USB device is suspended, windows does not wait for it to respond before entering a sleep or hibernate
mode. If you disable this feature, the system will simply return a failure to the driver when the driver attempts to enter suspend state. If the driver complies with Microsoft guidelines, it will simply retry the idle request at every expiration of its idle