From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Tosoni" Subject: RE: should RTS init in serial core be tied to CRTSCTS Date: Mon, 5 Mar 2007 18:39:29 +0100 Message-ID: <000e01c75f4d$3ab83620$2e01a8c0@acksys.local> References: <8bd0f97a0703050909n18386114kd2c0b2a108591641@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp24.msg.oleane.net ([62.161.4.24]:60638 "EHLO smtp24.msg.oleane.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752833AbXCESFQ (ORCPT ); Mon, 5 Mar 2007 13:05:16 -0500 Received: from RD2 ([194.206.161.7]) by smtp24.msg.oleane.net (MTA) with SMTP id l25HdYil018434 for ; Mon, 5 Mar 2007 18:39:34 +0100 In-Reply-To: <8bd0f97a0703050909n18386114kd2c0b2a108591641@mail.gmail.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org > true ... so ignoring the original motivation for change i posted, is > it really correct for the serial core to be forcing TIOCM_RTS at uart > startup even though the uart doesnt have CTSRTS flow control enabled ? > in other words, my change is agnostic of the console, and is done for > all uarts ... it should prob have a similar change in uart_shutdown() > though ... > -mike All UNIX drivers historically set RTS and DTR upon opening, and Windows drivers do the same... and this behaviour must be kept for compatibility I think... The only way I can imagine to keep RTS low on opens on selected ports, would be to set up a parameter in /proc or /sys ? maybe its management could be added to setserial ? I have a similar problem with many RS485 cards, when the port is opened the card takes the RS485 bus until RTS is turned back down by the opening process.