From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH 1/5] resources: add arch hook for preventing allocation in reserved areas Date: Mon, 13 Dec 2010 14:47:39 +0100 Message-ID: <20101213134739.GA27941@elte.hu> References: <20101208213606.13026.47657.stgit@bob.kio> <20101211201615.79186de7@jbarnes-desktop> <201012121420.57217.rjw@sisk.pl> <20101213054334.GA15856@helgaas.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx3.mail.elte.hu ([157.181.1.138]:40684 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757617Ab0LMNs2 (ORCPT ); Mon, 13 Dec 2010 08:48:28 -0500 Content-Disposition: inline In-Reply-To: <20101213054334.GA15856@helgaas.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Bjorn Helgaas Cc: "Rafael J. Wysocki" , Jesse Barnes , Linus Torvalds , Len Brown , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, "H. Peter Anvin" , Thomas Gleixner , Adam Belay , Matthew Garrett , Dan Williams * Bjorn Helgaas wrote: > > OK, so I guess the best thing we can do for 2.6.37 is to revert 1af3c2e (x86: > > allocate space within a region top-down), right? > > That's a possibility, but I'm not sure it's the best. It would avoid the nx6325 > landmine, but we could easily step on a different one on other machines. > > If Windows uses the end of available space first, that's the best-tested > territory, and I think it's better to try to stay in it rather revert 1af3c2e and > start mapping different territory that really isn't tested by Windows at all. > > On the nx6325, we stray out of that tested territory because Linux opens windows > on subtractive-decode bridges and allocates more space to CardBus bridges. > > I think it'd be fairly simple to leave subtractive-decode bridges alone, and that > might make the nx6325 work well enough for .37, even without the quirk. This > feels like a change that might be the right thing to do in general. Using > subtractive rather than positive decode would give up a little performance, but I > doubt it's important Is there a patch for that that people could try? The regression needs to be addressed one way or another: either by improving the "compatible with Windows" approach to actually work (without quirks), or by reverting to the tested-for-years Linux solution. ( What we always try to avoid is trading in a set of regressions for another set of regressions. That way lies madness, it can not result in reliable, provable progress. ) Thanks, Ingo