启动时候有这样的打印信息不知道是什么原因引起的？
usb 2-1: new full speed USB device using s5p-ohci and address 3
usb 2-1: device descriptor read/64, error -62
usb 2-1: device descriptor read/64, error -62
usb 2-1: new full speed USB device using s5p-ohci and address 4
usb 2-1: device not accepting address 4, error -62
usb 2-1: new full speed USB device using s5p-ohci and address 5
usb 2-1: device not accepting address 5, error -62
hub 2-0:1.0: unable to enumerate USB device on port 1
