Add modem-status-change wait queue to struct usb_serial_port that
subdrivers can use to implement TIOCMIWAIT.
Currently subdrivers use a private wait queue which may have been
released when waking up after device disconnected.
Note that we're adding a new wait queue rather than reusing the tty-port
one as we do not want to get woken up at hangup (yet).
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
e5b33dc9d1