Yes, I gone through this warning. It is because if i want to make this compilation warning free than i have to change the prototype of a open function pointer described in usb_serial_driver and changing the prototype over there would affect all the device driver lying in usb-serial category , which is definitely not recommended. Anyways i got your point . Thanks Abhishek-bist On 1 June 2015 at 20:00, Johan Hovold <johan@xxxxxxxxxx> wrote: > On Sat, May 30, 2015 at 06:47:20PM +0530, Abhishek Bist wrote: >> While designing a usb to uart converter driver open function I am using >> usb_serial_generic_open, but wouldn't find need to pass tty as an argument. >> As it is not performing any task for further significance. >> So, This patch proposed a change in usb_serial_generic_open >> function prototype which has struct tty_struct as a first argument. >> >> usb_serial_generic_open(struct tty_struct *tty, >> struct usb_serial_port *port); >> >> Signed-off-by: Abhishek Bist <ishubist@xxxxxxxxx> > >> diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h >> index 704a1ab..c8ed44a 100644 >> --- a/include/linux/usb/serial.h >> +++ b/include/linux/usb/serial.h >> @@ -318,8 +318,7 @@ static inline void usb_serial_console_disconnect(struct usb_serial *serial) {} >> /* Functions needed by other parts of the usbserial core */ >> extern struct usb_serial_port *usb_serial_port_get_by_minor(unsigned int minor); >> extern void usb_serial_put(struct usb_serial *serial); >> -extern int usb_serial_generic_open(struct tty_struct *tty, >> - struct usb_serial_port *port); >> +extern int usb_serial_generic_open(struct usb_serial_port *port); >> extern int usb_serial_generic_write_start(struct usb_serial_port *port, >> gfp_t mem_flags); >> extern int usb_serial_generic_write(struct tty_struct *tty, > > This does not work as usb_serial_generic_open is the default driver > callback. > > If you had compile tested your patch you would have seen the following > warning: > > linux/drivers/usb/serial/usb-serial.c: In function 'usb_serial_operations_init': > linux/drivers/usb/serial/usb-serial.c:1318:19: warning: assignment from incompatible pointer type > type->function = usb_serial_generic_##function; \ > ^ > linux/drivers/usb/serial/usb-serial.c:1326:2: note: in expansion of macro 'set_to_generic_if_null' > set_to_generic_if_null(device, open); > ^ > > Johan -- 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