From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751598AbWFQLZh (ORCPT ); Sat, 17 Jun 2006 07:25:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751605AbWFQLZh (ORCPT ); Sat, 17 Jun 2006 07:25:37 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:35276 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1751598AbWFQLZg (ORCPT ); Sat, 17 Jun 2006 07:25:36 -0400 Message-ID: <4493E6A9.4080604@garzik.org> Date: Sat, 17 Jun 2006 07:25:29 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.2 (X11/20060501) MIME-Version: 1.0 To: Greg KH CC: Brice Goglin , linux-pci@atrey.karlin.mff.cuni.cz, LKML Subject: Re: [RFC] Whitelist chipsets supporting MSI and check Hyper-transport capabilities References: <4493709A.7050603@myri.com> <20060617062840.GD31645@kroah.com> In-Reply-To: <20060617062840.GD31645@kroah.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.2 (----) X-Spam-Report: SpamAssassin version 3.1.3 on srv5.dvmed.net summary: Content analysis details: (-4.2 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Greg KH wrote: > On Fri, Jun 16, 2006 at 11:01:46PM -0400, Brice Goglin wrote: >> Several chipsets are known to not support MSI. Some support MSI but >> disable it by default. Thus, several drivers implement their own way to >> detect whether MSI works. >> >> We introduce whitelisting of chipsets that are known to support MSI and >> keep the existing backlisting to disable MSI for other chipsets. When it >> is unknown whether the root chipset support MSI or not, we disable MSI >> by default except if pci=forcemsi was passed. >> >> Whitelisting is done by setting a new PCI_BUS_FLAGS_MSI in the chipset >> subordinate bus. pci_enable_msi() thus starts by checking whether the >> root chipset of the device has the MSI or NOMSI flag set. > > Whitelisting looks all well and good today, and maybe for the rest of > the year. But what about 3 years from now when everyone has shaken all > of the MSI bugs out of their chipsets finally? Do you really want to > add a new quirk for _every_ new chipset that comes out? I don't think > that it is managable over the long run. > > I do like your checks to see if MSI is able to be enabled or not, and > maybe we can just invert them to mark those chips that do not support > MSI today? My gut feeling is: blacklist -> any Intel machines which fail (most work) blacklist -> any PCI Express which fails (most should work) whitelist -> any other situation which works Regards, Jeff