Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964928AbWHRVC0 (ORCPT ); Fri, 18 Aug 2006 17:02:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964929AbWHRVC0 (ORCPT ); Fri, 18 Aug 2006 17:02:26 -0400 Received: from caramon.arm.linux.org.uk ([217.147.92.249]:23816 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S964928AbWHRVCZ (ORCPT ); Fri, 18 Aug 2006 17:02:25 -0400 Date: Fri, 18 Aug 2006 22:02:17 +0100 From: Russell King To: Lee Revell Cc: markh@compro.net, Paul Fulghum , linux-kernel Subject: Re: Serial issue Message-ID: <20060818210217.GL21101@flint.arm.linux.org.uk> Mail-Followup-To: Lee Revell , markh@compro.net, Paul Fulghum , linux-kernel References: <1155923734.2924.16.camel@mindpipe> <44E602C8.3030805@microgate.com> <1155925024.2924.22.camel@mindpipe> <1155928885.2924.40.camel@mindpipe> <44E6221D.4040008@compro.net> <1155932916.2924.47.camel@mindpipe> <20060818203410.GJ21101@flint.arm.linux.org.uk> <1155934453.2924.56.camel@mindpipe> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1155934453.2924.56.camel@mindpipe> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2238 Lines: 49 On Fri, Aug 18, 2006 at 04:54:13PM -0400, Lee Revell wrote: > On Fri, 2006-08-18 at 21:34 +0100, Russell King wrote: > > On Fri, Aug 18, 2006 at 04:28:36PM -0400, Lee Revell wrote: > > > On Fri, 2006-08-18 at 16:25 -0400, Mark Hounschell wrote: > > > > Take it from someone who actually still uses dumb terminals every day, > > > > any thing over 9600 baud still requires some kind of flow control for > > > > reliable consistent operation. Software (Xon/Xoff) and or hardware > > > > (RTS/RTS/DTE) flow control. > > > > > > > > > > Any idea why the serial console does not work at all with flow control > > > enabled (regardless of whether the host runs Linux or another OS)? > > > > I use serial console with flow control and haven't seen any problems. > > > > Can you describe your issue with more detail? > > > > What actions are required to get this "does not work at all" state? > > > > Are you passing a kernel parameter to enable flow control? > > > > Are you saying that you get kernel messages if flow control is disabled, > > but if you subsequently enable flow control, and provoke a kernel message, > > you don't see any messages? When you re-disable flow control, you do? > > > > I believe the flow control problem is due to my cable. > > Anyway I don't want to confuse the issue: the problem that I want to > solve (or at least explain) is that while the serial console works with > the host serial port in both interrupt and polled mode, kermit file > transfers only work in polled mode ("setserial /dev/ttyS0 irq 0"). If you're talking about sending via a polled port, the average data rate is probably slow enough that the receiving side can keep up. But in interrupt mode, it's probably a stream of characters at the specified baud rate, which results in lost characters. That explaination doesn't resolve the receiving via a polled port though. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/