From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: Re: [PATCH 2/2] usb: gadget serial: Honour termios CLOCAL on disconnect Date: Mon, 27 Oct 2014 13:11:14 -0400 Message-ID: <544E7CB2.2020200@hurleysoftware.com> References: <1414346490-19307-1-git-send-email-kyosti.malkki@gmail.com> <1414346490-19307-3-git-send-email-kyosti.malkki@gmail.com> <20141027133837.GC8537@saruman> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20141027133837.GC8537@saruman> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: balbi-l0cyMroinI0@public.gmane.org, =?UTF-8?B?S3nDtnN0aSBNw6Rsa2tp?= Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Greg KH , linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-serial@vger.kernel.org On 10/27/2014 09:38 AM, Felipe Balbi wrote: > Hi, >=20 > On Sun, Oct 26, 2014 at 08:01:30PM +0200, Ky=C3=B6sti M=C3=A4lkki wro= te: >> There are applications where it is desirable to not hangup ttyGS* wh= en >> USB disconnect is detected. USB host side of communication may >> power-cycle periodically or there may be the actual need to physical= ly >> disconnect and reconnect USB cable temporarily. >> >> USB disconnects on serial gadget are comparable to loss of Carrier D= etect >> of conventional UARTs. With the change, if ttyGS* has termios CLOCAL= flag >> set, disconnect on USB does not hangup the TTY. >> >> Signed-off-by: Ky=C3=B6sti M=C3=A4lkki >> --- >> 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/ga= dget/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 =3D 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 =3D port->port.tty; >=20 > declare above as Sergei said. >=20 >> + if (tty) { >=20 > is there any situation where tty would be NULL here ? >=20 >> + if (tty->termios.c_cflag & CLOCAL) >> + stop_tty(tty); >> + else >> + tty_hangup(tty); >=20 > this I'll defer to Greg who also maintains tty. I'm curious what happens without stop_tty(). The tty is restartable from userspace with tcflow(fd, TCOOFF); tcflow(fd, TCOON); Regards, Peter Hurley -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html