linux-kernel - Re: [PATCH]TTY: Fix tty can't be restarted by TCXONC ioctl request

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Date:	Wed, 08 May 2013 11:18:07 -0400
From:	Peter Hurley <peter@...leysoftware.com>
To:	Wang YanQing <udknight@...il.com>
CC:	Greg KH <gregkh@...uxfoundation.org>, jslaby@...e.cz,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH]TTY: Fix tty can't be restarted by TCXONC ioctl request

On 05/08/2013 09:16 AM, Wang YanQing wrote:
> On Tue, May 07, 2013 at 07:02:00PM -0700, Greg KH wrote:
>> What about Peter's comments on this patch?
>>
> Peter's comments will import policy,
>
> I means we should let userspace to decide whether
> and when to restart tty with the mechanism of TCXONC
> instead of restart tty accidental when make n_tty_set_termios
> call.

There would be no accidental restart. Userspace is specifically
disabling user-controlled output flow control by clearing
IXON in termios. Userspace is _expecting_ a 'started' tty.

If you insist that this must be controllable from userspace,
then that is already possible:

	tcflow(fd, TCOOFF);
	tcflow(fd, TCOON);


Regards,
Peter Hurley

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