From: Grant Edwards <grant.b.edwards@gmail.com>
To: linux-serial@vger.kernel.org
Subject: Re: New serial card development
Date: Tue, 23 Oct 2012 20:41:52 +0000 (UTC) [thread overview]
Message-ID: <k66veg$1h4$1@ger.gmane.org> (raw)
In-Reply-To: 20121023203102.GA28626@thunk.org
On 2012-10-23, Theodore Ts'o <tytso@mit.edu> wrote:
> On Tue, Oct 23, 2012 at 06:45:51PM +0000, Grant Edwards wrote:
>> FWIW, in some products we're planning that will require support for
>> various industrial serial protocols, I'm leaning towards abandoning
>> the tty driver approach and writing a stand-alone character device
>> driver. The byte-stream oriented tty/line-discipline layer just
>> doesn't fit well when dealing with frame-oriented industrial protocols
>> that depend on things like 9th bit addressing and detecting
>> sub-millisecond inter-byte timeouts.
>
> You might want to take a look at how the ppp line discipline (which
> is obviously highly packet oriented) works. One advantage of doing
> things that way is if you have a multiport serial card, where some
> ports want to play this packet-oriented approach, and other cards
> might be connected to a traditional modem or terminal sort of device,
> you won't have to figure out how to share a PCI board between two
> different drivers, allocating one port to the traditional tty/serial
> driver, and another one to your new driver, etc.
Thanks for the suggestion. I did look into line-disciplines briefly
quite a while back. Most of the information I found implied that
adding a line disciplilne wasn't something you could do at run-time by
loading a user-built module -- it would require recompiling parts of
the kernel. Articles made statements about having to modify kernel
include files like tty.h. If that's wrong, then a line discipline
might be a good option.
--
Grant Edwards grant.b.edwards Yow! I'm having a
at quadrophonic sensation
gmail.com of two winos alone in a
steel mill!
next prev parent reply other threads:[~2012-10-23 20:42 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-09 18:43 New serial card development Matt Schulte
2012-10-14 9:37 ` Theodore Ts'o
2012-10-15 19:08 ` Matt Schulte
2012-10-15 23:26 ` Alan Cox
2012-10-16 2:32 ` Theodore Ts'o
2012-10-17 20:24 ` Matt Schulte
2012-10-19 21:21 ` Theodore Ts'o
2012-10-23 16:27 ` Matt Schulte
2012-10-23 16:31 ` Matt Schulte
2012-10-23 18:38 ` Greg KH
2012-10-29 20:04 ` Matt Schulte
2012-10-31 21:55 ` Matt Schulte
2012-11-01 22:03 ` Matt Schulte
2012-11-01 22:26 ` Alan Cox
2012-11-02 18:47 ` Matt Schulte
2012-11-02 20:21 ` Alan Cox
2012-10-23 18:06 ` Grant Edwards
2012-10-23 18:26 ` Alan Cox
2012-10-23 18:45 ` Grant Edwards
2012-10-23 19:16 ` Greg KH
2012-10-23 19:42 ` Grant Edwards
2012-10-23 20:10 ` Greg KH
2012-10-23 19:24 ` Alan Cox
2012-10-23 19:48 ` Grant Edwards
2012-10-23 20:31 ` Theodore Ts'o
2012-10-23 20:41 ` Grant Edwards [this message]
[not found] ` <CAJp1Oe6k7NWqdbYkJnd787JiT55-wSbG+tX1tP7Cy-oPShdVaA@mail.gmail.com>
2012-10-17 20:23 ` Matt Schulte
2012-10-17 21:53 ` Alan Cox
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