Hi, Recently, there is one bug report from Ubuntu community: USB 2.0 Ports Dont Work on Sony Vaio Laptop and the problem exists on upstream kernel too. The built-in two USB 2.0 devices can be recognized correctly, but external devices can't be recognized when the device is connected to USB 2.0 port. Also, the USB 2.0 bus can be waken up successfully via /sys/bus/devices/.../power/control, but still can't find external connected devices, and no any 'dmesg' log with CONFIG_USB_DEBUG enabled after the device is plugged into 2.0 ports. See detailed log in below link: https://bugs.launchpad.net/bugs/1172908 No such problem on Windows. Thanks, -- Ming Lei -- 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