From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Edwards Subject: Re: New serial card development Date: Tue, 23 Oct 2012 19:42:28 +0000 (UTC) Message-ID: References: <20121014093704.GA6207@thunk.org> <20121016002608.64b33de5@pyramind.ukuu.org.uk> <20121016023226.GA17446@thunk.org> <20121019212158.GB4721@thunk.org> <20121023192633.18849645@pyramind.ukuu.org.uk> <20121023191604.GA1942@kroah.com> Return-path: Received: from plane.gmane.org ([80.91.229.3]:55943 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756806Ab2JWTmr (ORCPT ); Tue, 23 Oct 2012 15:42:47 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1TQkNH-0002xt-9c for linux-serial@vger.kernel.org; Tue, 23 Oct 2012 21:42:51 +0200 Received: from dsl.comtrol.com ([64.122.56.22]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 23 Oct 2012 21:42:51 +0200 Received: from grant.b.edwards by dsl.comtrol.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 23 Oct 2012 21:42:51 +0200 Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org On 2012-10-23, Greg KH 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. When I add in the lack of >> long-term stability in the tty API it seems like it might not be such >> a bad idea to give up trying to make the tty abstraction fit a use >> case that's just nothing like a teletype. > > What do you mean "lack of long-term stability"? The userspace tty api > hasn't ever changed or broken. I meant the in-kernel api. > Don't focus on in-kernel api, It's my job to focus on the in-kernel api. > that's always going to change, no matter what interface you choose to > use in the kernel. Maybe it's just my perception, but the the tty API seems to change a more than the plain character-device API. -- Grant Edwards grant.b.edwards Yow! I wish I was on a at Cincinnati street corner gmail.com holding a clean dog!