me ports not switchable by the OS. There are two more registers that contains the information of the switchable and non-switchable ports. This patch adds the checking code for the two register so that only the switchable ports are altered. This patch should be backported to kernels as old as 3.0, that contain commit ID 69e848c2090aebba5698a1620604c7dccb448684 "Intel xhci: Support EHCI/xHCI port switching." Signed-off-by: Keng-Yu Lin Signed-off-by: Sarah Sharp Cc: stable@vger.kernel.org \:Kϗ7x