The qcserial driver fails to expose the .tiocmget and .tiocmset methods available from usb_wwan. These methods are required by ioctl commands dealing with the modem control signals DTR, RTS, etc. With these methods not set ioctl calls intended to control the DTR state will fail. For example, pppd drops and raises DTR in preparation to dialing the modem, which handles the case of the modem already being connected by making it hang up and return to command mode. DTR control being unavailable will lead to a protracted failure to connect as the modem will be stuck in a state not responsive to command. I have tested that with this patch the described case is handled successfully. There is an analogous method for .ioctl available from usb_wwan (as used in option.c) but I conservatively omitted that for lack of familiarity. Signed-off-by: Magnus Lynch <maglyx@xxxxxxxxx> --- Apologies for bad formatting. Further attempting to resolve that. diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c index fd509ed6c..4ac137d 100644 --- a/drivers/usb/serial/qcserial.c +++ b/drivers/usb/serial/qcserial.c @@ -454,6 +454,8 @@ static void qc_release(struct usb_serial *serial) .write = usb_wwan_write, .write_room = usb_wwan_write_room, .chars_in_buffer = usb_wwan_chars_in_buffer, + .tiocmget = usb_wwan_tiocmget, + .tiocmset = usb_wwan_tiocmset, .attach = qc_attach, .release = qc_release, .port_probe = usb_wwan_port_probe, -- 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
