Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756892AbXEYEdG (ORCPT ); Fri, 25 May 2007 00:33:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751336AbXEYEc4 (ORCPT ); Fri, 25 May 2007 00:32:56 -0400 Received: from smtp1.linux-foundation.org ([207.189.120.13]:49151 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751332AbXEYEcz (ORCPT ); Fri, 25 May 2007 00:32:55 -0400 Date: Thu, 24 May 2007 21:31:57 -0700 From: Andrew Morton To: ebiederm@xmission.com (Eric W. Biederman) Cc: Greg Kroah-Hartman , Jay Cliburn , Grzegorz Krzystek , Andi Kleen , ninex@o2.pl, , , Michael Ellerman , David Miller , Tony Luck , Linus Torvalds Subject: Re: [PATCH 1/2] msi: Invert the sense of the MSI enables. Message-Id: <20070524213157.1d39458f.akpm@linux-foundation.org> In-Reply-To: References: <200705122146.l4CLkH6q012322@fire-2.osdl.org> <20070513014622.c5702928.akpm@linux-foundation.org> <46470209.9000502@bellsouth.net> <46470515.50000@NineX.eu.org> <464707F7.6080600@bellsouth.net> <20070513204407.7ba35010@osprey.hogchain.net> <4647FA38.3090108@NineX.eu.org> <46480EA5.40400@NineX.eu.org> <20070514053406.478bf93f@osprey.hogchain.net> <20070514093829.377e04bc@osprey.hogchain.net> <20070514160005.627435e3@osprey.hogchain.net> <20070515212200.517fcba2@osprey.hogchain.net> <20070516185225.3f3ac082@osprey.hogchain.net> <20070522204103.134bf5a2@osprey.hogchain.net> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) 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: 1458 Lines: 30 On Thu, 24 May 2007 22:19:09 -0600 ebiederm@xmission.com (Eric W. Biederman) wrote: > Currently we blacklist known bad msi configurations which means we > keep getting MSI enabled on chipsets that either do not support MSI, > or MSI is implemented improperly. Since the normal IRQ routing > mechanism seems to works even when MSI does not, this is a bad default > and causes non-functioning systems for no good reason. > > So this patch inverts the sense of the MSI bus flag to only enable > MSI on known good systems. I am seeding that list with the set of > chipsets with an enabled hypertransport MSI mapping capability. Which > is as close as I can come to an generic MSI enable. So for actually > using MSI this patch is a regression, but for just having MSI enabled > in the kernel by default things should just work with this patch > applied. > > People can still enable MSI on a per bus level for testing by writing > to sysfs so discovering chipsets that actually work (assuming we are > using modular drivers) should be pretty straight forward. Yup. Do we have a feel for how much performace we're losing on those systems which _could_ do MSI, but which will end up defaulting to not using it? - 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/