On Mon, Jan 20, 2020 at 09:06:18AM +0300, Sergey Organov wrote:
> Michał Mirosław <mirq-linux@xxxxxxxxxxxx> writes:
>
> > On Fri, Jan 17, 2020 at 08:29:33AM +0300, Sergey Organov wrote:
> >> --- a/drivers/usb/gadget/function/u_serial.c
> >> +++ b/drivers/usb/gadget/function/u_serial.c
> >> @@ -563,6 +563,8 @@ static int gs_start_io(struct gs_port *port)
> >>
> >> /* unblock any pending writes into our circular buffer */
> >> if (started) {
> >> + pr_debug("gs_start_tx: ttyGS%d\n", port->port_num);
> >> + gs_start_tx(port);
> >> tty_wakeup(port->port.tty);
> >
> > The tty_wakeup() will be called from gs_start_tx(), so should be removed
> > from here.
>
> Not exactly. tty_wakeup() will be called from gs_start_tx() only when
> there has been something actually transferred from the buffer. I didn't
> want to change behavior when the buffer is empty, so I kept the explicit
> tty_wakeup() call in place, intentionally. Please let me know if you
> still think it should be removed.
Indeed it is as you describe. You might add an argument that initializes
do_tty_wake, but I'm not sure saving one tty_wakeup() on open is worth
the trouble.
> > The pr_debug() in other callers of gs_start_tx() say:
> > "caller: start ttyGS%d".
>
> ???
>
> $ git co gregkh/tty-next && grep -r 'caller: start tty' .
> HEAD is now at 7788f54... serial_core: Remove unused member in uart_port
> $
Replace 'caller' with a function calling gs_start_io().
Best Regards,
Michał Mirosław
