Serdev does not use the file abstraction and specifically there will never be anyone polling a file descriptor for POLLOUT events. Just use plain wake_up_interruptible() in the write_wakeup callback and document why it's there. Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>