On Sat, 11 Jul 2015, James wrote: > I have an external drive that has an activity LED. > It would be nice if it told me if it was connected to a USB2 or USB3 port. > Is it possible for devices to know what they are connected to? How would you expect the drive to tell you what sort of port it is connected to? By shining an LED of a different color? Green for USB-2 and blue for USB-3, for example? In general it is not possible for a device to know what sort of port it is connected to. It only knows what speed the connection runs at. If the connection runs at SuperSpeed then the port is definitely USB-3. But if the connection is high speed then the port could be USB-3 or USB-2. If the connection is full speed then the port could even be USB-1.1. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
