From owner-freebsd-current@FreeBSD.ORG Tue Mar 11 00:56:19 2008 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id ED5451065672 for ; Tue, 11 Mar 2008 00:56:19 +0000 (UTC) (envelope-from t_uemura@macome.co.jp) Received: from smtp12.dti.ne.jp (smtp12.dti.ne.jp [202.216.231.187]) by mx1.freebsd.org (Postfix) with ESMTP id A11C38FC22 for ; Tue, 11 Mar 2008 00:56:19 +0000 (UTC) (envelope-from t_uemura@macome.co.jp) Received: from towerrecords.dyndns.org (221x254x158x92.ap221.ftth.ucom.ne.jp [221.254.158.92]) by smtp12.dti.ne.jp (3.11s) with ESMTP AUTH id m2B0fote015420 for ; Tue, 11 Mar 2008 09:41:50 +0900 (JST) Received: by towerrecords.dyndns.org (Postfix, from userid 58) id B9F7943B3; Tue, 11 Mar 2008 09:41:50 +0900 (JST) X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on towerrecords.dyndns.org Received: from [127.0.0.1] (towerrecords [192.168.0.1]) by towerrecords.dyndns.org (Postfix) with ESMTP id 5440B43A3 for ; Tue, 11 Mar 2008 09:41:47 +0900 (JST) From: UEMURA Tetsuya To: freebsd-current@freebsd.org Sender: t_uemura@macome.co.jp MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.44 [ja] Message-Id: <20080311004147.5440B43A3@towerrecords.dyndns.org> Date: Tue, 11 Mar 2008 09:41:47 +0900 (JST) X-Mailman-Approved-At: Tue, 11 Mar 2008 02:16:00 +0000 Subject: uart(4) 16550A FIFO latency too long X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Mar 2008 00:56:20 -0000 Hi there. I have a timing sensitive sensor device connected to PC with serial ports. In order to gather data from the device correctly, I have to set the 16550A FIFO interrupt trigger level lower than the default FCR_RX_MEDH to FCR_RX_MEDL or FCR_RX_LOW. However, there's no tunable in uart(4) to set these levels manually, so I've added some lines to uart(4) and now I've been able to set the level via device.hints. Please someone review the following PR. http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/121421 . Thank in advance. -- UEMURA Tetsuya