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

From: Wang YanQing
Date: Wed May 08 2013 - 13:13:05 EST


On Wed, May 08, 2013 at 11:18:07AM -0400, Peter Hurley wrote:
> 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);

Indeed you can't do what you said with TCOOFF and TCOON
if you read the codes, that's what this patch fix.

Thanks.
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