Subject: Re: Linux v2.6.9 (Strange tty problem?)
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Paul Fulghum <paulkf@microgate.com>
Cc: Paul <set@pobox.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Linus Torvalds <torvalds@osdl.org>
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Date: Thu, 21 Oct 2004 16:37:33 +0100
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On Iau, 2004-10-21 at 14:20, Paul Fulghum wrote:
> This restores the original behavior for
> devices that have not yet implemented ldisc->hangup()
> and should work with the new locking.

Unfortunately that re-introduces another existing unfixed problem. The
N_TTY layer echoes bytes back up the stack into the drivers which are in
hangup state.

I did try calling the set_tty_ldisc but not every driver in that
situation then did the right thing and I got stuck ttys too. I think
that is fixed but 2.6.9rc4 was a bit tight. 

If you want to do the tty_ldisc_set then add a "nulldisc" that just eats
anything it is fed and EOF's anything the other direction. That
would avoid the driver reflect crash I suspect.

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