Hi,
On Sun, Oct 26, 2014 at 08:01:30PM +0200, Kyösti Mälkki wrote:
> There are applications where it is desirable to not hangup ttyGS* when
> USB disconnect is detected. USB host side of communication may
> power-cycle periodically or there may be the actual need to physically
> disconnect and reconnect USB cable temporarily.
>
> USB disconnects on serial gadget are comparable to loss of Carrier Detect
> of conventional UARTs. With the change, if ttyGS* has termios CLOCAL flag
> set, disconnect on USB does not hangup the TTY.
>
> Signed-off-by: Kyösti Mälkki <kyosti.mal...@gmail.com>
> ---
> drivers/usb/gadget/function/u_serial.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/u_serial.c
> b/drivers/usb/gadget/function/u_serial.c
> index 491082a..e68ffd7 100644
> --- a/drivers/usb/gadget/function/u_serial.c
> +++ b/drivers/usb/gadget/function/u_serial.c
> @@ -1254,8 +1254,13 @@ void gserial_disconnect(struct gserial *gser)
> gser->ioport = NULL;
> if (port->port.count > 0 || port->openclose) {
> wake_up_interruptible(&port->drain_wait);
> - if (port->port.tty)
> - tty_hangup(port->port.tty);
> + struct tty_struct *tty = port->port.tty;
declare above as Sergei said.
> + if (tty) {
is there any situation where tty would be NULL here ?
> + if (tty->termios.c_cflag & CLOCAL)
> + stop_tty(tty);
> + else
> + tty_hangup(tty);
this I'll defer to Greg who also maintains tty.
--
balbi
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