Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752996AbXJVX6S (ORCPT ); Mon, 22 Oct 2007 19:58:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751222AbXJVX6D (ORCPT ); Mon, 22 Oct 2007 19:58:03 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:59658 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751115AbXJVX6A (ORCPT ); Mon, 22 Oct 2007 19:58:00 -0400 Date: Mon, 22 Oct 2007 16:58:22 -0700 (PDT) Message-Id: <20071022.165822.126577184.davem@davemloft.net> To: khc@pm.waw.pl Cc: jeff@garzik.org, barkalow@iabervon.org, linas@austin.ibm.com, chunhao.huang@hotmail.com, gregkh@suse.de, htejun@gmail.com, brice.goglin@gmail.com, david.gaarenstroom@gmail.com, linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, shane.huang@amd.com, linux-ide@vger.kernel.org, brice@myri.com Subject: Re: [patch] PCI: disable MSI on more ATI NorthBridges From: David Miller In-Reply-To: References: <471D0ADC.7000005@garzik.org> X-Mailer: Mew version 5.1.52 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1526 Lines: 34 From: Krzysztof Halasa Date: Tue, 23 Oct 2007 01:40:18 +0200 > Jeff Garzik writes: > > > In general it is documented that INTX_DISABLE should apply only to > > INTx# so devices that disable MSI based on that bit are out of spec. > > The wording is: > 10: This bit disables the device from asserting INTx#. A value of 0 > enables the assertion of its INTx# signal. A value of 1 disables the > assertion of its INTx# signal. This bit's state after RST# is 0. Refer > to Section 6.8.1.3 for control of MSI. > > So strictly speaking it mandates disabling/enabling INTx but says > nothing about other things (e.g. MSI). Some common sense dictates > it shouldn't disable MSI, I guess. Right, and every vendor I've spoken to who had the INTX_DISABLE bug clearly acknowledged that it was a bug in their RTL design and that they considered the spec to be clear on this matter in that INTX_DISABLE should not influence MSI in any way. > The "MSI Enable" description doesn't leave any doubt: > 0: MSI Enable: If 1, the function is permitted to use MSI to request > service and is prohibited from using its INTx# pin [...] Things get more complicated with PCI-Express because INTx# isn't an out-of-band "pin", but rather a message sent over the bus :-) - 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/