Re: [PATCH tty-next 0/4] tty: Fix ^C echo

[Peter Hurley]

On 12/08/2013 08:12 PM, Greg Kroah-Hartman wrote:
> On Mon, Dec 02, 2013 at 04:12:01PM -0500, Peter Hurley wrote:
> > Greg,
> >
> > Sometimes when interrupting terminal output, the '^C' won't be echoed
> > until more output is echoed. This is fairly repeatable by interrupting
> > 'cat large-file'.
> >
> > The common reason for this is because the tty write buffer is full,
> > even though the write buffer _should_ have been flushed already.
> > Because of a known deadlock, the pty driver does not perform a
> > write buffer flush in its flush_buffer() method.
> >
> > [Refer to the FIXME in pty_flush_buffer() from commit
> > d945cb9cce20ac7143c2de8d88b187f62db99bdc,
> > 'pty: Rework the pty layer to use the normal buffering logic']
> >
> > Patch 1 fixes a stale comment.
> > Patch 2 adds the necessary interfaces to avoid direct linkage
> > between the N_TTY line discipline and the pty driver.
> > Patch 3 avoids the deadlock while performing the write buffer flush.
> > Patch 4 fixes a less common condition introduced by the echo batch
> > processing added in 3.12.
> >
> > Alan,
> >
> > I cc'd you because of your recent involvement in other
> > tty patches/bug fixes and because it's your FIXME comment.
> > Feel free to ignore and/or let me know you would prefer not to
> > be bothered.
>
> Peter, this series doesn't fix the ^C echo problem that Karl recently
> reported, so I'll hold off in applying it for now.

Yeah, please discard this. It does fix some problems but I don't really
like how it goes about fixing them. I've been exploring some ideas
based on my discussion with Alan but nothing fruitful yet.

Regards,
Peter Hurley

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