From owner-cvs-src@FreeBSD.ORG Thu May 27 07:09:27 2004 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E6EAF16A4CE for ; Thu, 27 May 2004 07:09:27 -0700 (PDT) Received: from hanoi.cronyx.ru (hanoi.cronyx.ru [144.206.181.53]) by mx1.FreeBSD.org (Postfix) with ESMTP id 25E7843D2F for ; Thu, 27 May 2004 07:09:27 -0700 (PDT) (envelope-from rik@cronyx.ru) Received: (from root@localhost) by hanoi.cronyx.ru id i4RE5Cj4048681 for cvs-src@FreeBSD.org.checked; (8.12.8/vak/2.1) Thu, 27 May 2004 18:05:12 +0400 (MSD) (envelope-from rik@cronyx.ru) Received: from cronyx.ru (hi.cronyx.ru [144.206.181.94]) by hanoi.cronyx.ru with ESMTP id i4RE4U9g048583; (8.12.8/vak/2.1) Thu, 27 May 2004 18:04:30 +0400 (MSD) (envelope-from rik@cronyx.ru) Message-ID: <40B5F5AC.4080500@cronyx.ru> Date: Thu, 27 May 2004 18:05:32 +0400 From: Roman Kurakin User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.6b) Gecko/20031208 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Bruce Evans References: <200405262159.i4QLx1cQ072334@repoman.freebsd.org> <20040527123826.R8527@gamplex.bde.org> In-Reply-To: <20040527123826.R8527@gamplex.bde.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: Thomas Moestl cc: cvs-src@FreeBSD.org cc: src-committers@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/uart uart_dev_ns8250.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 May 2004 14:09:28 -0000 Bruce Evans wrote: >On Wed, 26 May 2004, Thomas Moestl wrote: > > > >>tmm 2004/05/26 14:59:01 PDT >> >> FreeBSD src repository >> >> Modified files: >> sys/dev/uart uart_dev_ns8250.c >> Log: >> It seems that clearing the MCR_IE bit in the modem control register >> does not reliably prevent the triggering of interrupts for all supported >> configurations. Thus, the FIFO size probe could cause an interrupt, >> which could lead to an interrupt storm in the shared interrupt case. >> >> > >s/It seems that clearing/Clearing/. Clearing MCR_IE disables the device's >line driver for the irq. At least on old i386 isa systems, the line driver >is normally connected to a tri-state latch which floats high due to a weak >pullup when all its inputs are disabled. So "disabling" interrupts by > > As far as I know some modern UARTS do not support this feature. For example, Exar 17C158. rik