From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Subject: Re: [Bug #15124] PCI host bridge windows ignored (works with pci=use_crs) Date: Wed, 27 Jan 2010 13:02:10 -0800 Message-ID: <20100127130210.6fe94255@jbarnes-piketon> References: <201001270945.17113.bjorn.helgaas@hp.com> <20100127085337.6ff06f6e@jbarnes-piketon> <201001271345.54454.bjorn.helgaas@hp.com> <20100127125905.17db320f@jbarnes-piketon> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100127125905.17db320f@jbarnes-piketon> Sender: linux-pci-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Jesse Barnes Cc: Linus Torvalds , Bjorn Helgaas , Yinghai Lu , Jeff Garrett , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Linux PCI , Myron Stowe , Matthew Garrett , Ingo Molnar On Wed, 27 Jan 2010 12:59:05 -0800 Jesse Barnes wrote: > On Wed, 27 Jan 2010 12:50:12 -0800 (PST) > Linus Torvalds wrote: > > > > > > > On Wed, 27 Jan 2010, Bjorn Helgaas wrote: > > > > > > Without intel_bus.c, we essentially assume config 1 all the time. > > > If we keep intel_bus.c and this patch for .33, things should work > > > for configs 1 and 4. Adding support for config 4 is good. > > > > Quite frankly, is there any major downside to just disabling/removing > > intel_bus.c for 2.6.33? If we're not planning on having it in the long run > > anyway - or even if we are, but we can't be really happy about the state > > of it as it would be in 2.6.33, not using it at all seems to be the > > smaller headache. > > > > The machines that it helps are also the machines where you can fix things > > up with 'use_csr', no? And they are pretty rare, and they didn't use to > > work without that use_csr in 2.6.32 either, so it's not even a regression. > > > > Am I missing something? > > No that's the plan. intel_bus.c was a good effort, but it's just too > different from what Windows does, and it'll always be behind. We'll > disable it for 2.6.33 and try again to move to _CRS in 2.6.34 (but > fixing the problem with large numbers of _CRS resources this time). Should say "disable it for 2.6.33 for all but multi-IOH configs", which seem to be fairly rare anyway, and were what intel_bus.c was designed to accommodate. On the one machine that motivated it, use_crs was broken (though it likely isn't now), so it seems the safest route. -- Jesse Barnes, Intel Open Source Technology Center