From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261358AbUDAAoh (ORCPT ); Wed, 31 Mar 2004 19:44:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261439AbUDAAoh (ORCPT ); Wed, 31 Mar 2004 19:44:37 -0500 Received: from bay2-f51.bay2.hotmail.com ([65.54.247.51]:22537 "EHLO hotmail.com") by vger.kernel.org with ESMTP id S261358AbUDAAof (ORCPT ); Wed, 31 Mar 2004 19:44:35 -0500 X-Originating-IP: [209.172.74.2] X-Originating-Email: [idht4n@hotmail.com] From: "David L" To: linux-kernel@vger.kernel.org Subject: serial port canonical mode weirdness? Date: Wed, 31 Mar 2004 16:44:32 -0800 Mime-Version: 1.0 Content-Type: text/plain; format=flowed Message-ID: X-OriginalArrivalTime: 01 Apr 2004 00:44:32.0832 (UTC) FILETIME=[7FAB0C00:01C41782] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org When I configure a serial port for canonical mode (newtio.c_lflag = ICANON), I get behavior that isn't what I'd expect. If I send >4095 characters that don't contain an end-of-line and then an end of line, the number of characters read is 1. If I then start sending shorter lines, one character is read for each end-of-line that is sent. For example, if the limit was 10 instead of 4096, if the received data was: 0123456789\n The data returned by the driver would be: 0 (I would expect 0123456789\n to be returned) Then if you send "A\n" The data returned will be "1" Then if you send "B\n" The data returned will be "2" And so on. When it's in this state and you send "\n\n", it returns 4096 characters and then starts acting like I would expect again. I've also found that when it's in this state and you send a few lines in rapid succession, the call to read will return 0 bytes and never returns any more good data. Is this a kernel bug or an ignorant user? I might expect some data to be lost if a buffer overruns, but I didn't expect this behavior. Thanks: David _________________________________________________________________ MSN Toolbar provides one-click access to Hotmail from any Web page – FREE download! http://toolbar.msn.com/go/onm00200413ave/direct/01/