From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:57412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726226AbeLDQPV (ORCPT ); Tue, 4 Dec 2018 11:15:21 -0500 Date: Tue, 4 Dec 2018 17:15:18 +0100 From: Greg Kroah-Hartman To: Johan Hovold Cc: linux-usb@vger.kernel.org, Jarkko Nikula , Jiri Slaby , linux-kernel@vger.kernel.org, stable , Florian Zumbiehl Subject: Re: [PATCH] USB: serial: console: fix reported terminal settings Message-ID: <20181204161518.GA17941@kroah.com> References: <20181204155904.GC18087@localhost> <20181204160036.24625-1-johan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181204160036.24625-1-johan@kernel.org> Sender: stable-owner@vger.kernel.org List-ID: On Tue, Dec 04, 2018 at 05:00:36PM +0100, Johan Hovold wrote: > The USB-serial console implementation has never reported the actual > terminal settings used. Despite storing the corresponding cflags in its > struct console, this was never honoured on later tty open() where the > tty termios would be left initialised to the driver defaults. > > Unlike the serial console implementation, the USB-serial code calls > subdriver open() already at console setup. While calling set_termios() > before open() looks like it could work for some USB-serial drivers, > others definitely do not expect this, so modelling this after serial > core is going to be intrusive, if at all possible. > > Instead, use a (renamed) tty helper to save the termios data used at > console setup, so that the tty termios reflects the actual terminal > settings after a subsequent tty open(). > > Note that the calls to tty_init_termios() (tty_driver_install()) and > tty_save_termios() are serialised using the disconnect mutex. > > This specifically fixes a regression that was triggered by a recent > change adding software flow control to the pl2303 driver: a getty trying > to disable flow control while leaving the baud rate unchanged would now > also set the baud rate to the driver default (prior to the flow-control > change this had been a noop). > > Fixes: 7041d9c3f01b ("USB: serial: pl2303: add support for tx xon/xoff flow control") > Cc: stable # 4.18 > Reported-by: Jarkko Nikula > Cc: Florian Zumbiehl > Signed-off-by: Johan Hovold > --- > drivers/tty/tty_io.c | 11 +++++++++-- > drivers/usb/serial/console.c | 2 +- > include/linux/tty.h | 1 + > 3 files changed, 11 insertions(+), 3 deletions(-) Ah, messy :) Want me to take this through my tty tree? thanks, greg k-h