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
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
