Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 22 Mar 2001 15:56:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 22 Mar 2001 15:56:48 -0500 Received: from www.microgate.com ([216.30.46.105]:23307 "EHLO sol.microgate.com") by vger.kernel.org with ESMTP id ; Thu, 22 Mar 2001 15:56:34 -0500 Message-ID: <00b101c0b312$7385ddb0$0c00a8c0@diemos> From: "Paul Fulghum" To: "Geir Thomassen" , "Theodore Tso" , In-Reply-To: <3ABA42A8.A806D0E7@powertech.no> <20010322140852.A4110@think> <3ABA6167.309E6DB2@powertech.no> Subject: Re: Serial port latency Date: Thu, 22 Mar 2001 14:55:38 -0600 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2919.6700 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > The serial port chip is 16550A, which has a built in fifo. Can this be > the source of my problems ? > > Geir I thought about that. If the number of receive bytes in the RX FIFO is less that the trigger level then a timeout has to occur before getting the next receive data interrupt. The 16550AF data book says that this timeout is 4 characters from when the last byte is received. This is a maximum of 160ms at 300bps (when using 12bit characters: 1 start + 8 data + parity + 2 stop). So this would be smaller at 9600 and could not account for the 500ms delay. Paul Fulghum paulkf@microgate.com Microgate Corporation www.microgate.com - 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/