From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932206AbaCQAIN (ORCPT ); Sun, 16 Mar 2014 20:08:13 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:55040 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932179AbaCQAIL (ORCPT ); Sun, 16 Mar 2014 20:08:11 -0400 From: "Rafael J. Wysocki" To: Borislav Petkov Cc: Stephane Eranian , lkml , x86 , Bjorn Helgaas , Linux PCI , ACPI Devel Maling List , Zhang Rui , Yinghai Lu , "H. Peter Anvin" Subject: Re: Info: mapping multiple BARs. Your kernel is fine. Date: Mon, 17 Mar 2014 01:23:37 +0100 Message-ID: <6878235.CLHeQJJUpt@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.14.0-rc6+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1425376.F2qgSAxAbW@vostro.rjw.lan> References: <20140224162400.GE16457@pd.tnic> <1425376.F2qgSAxAbW@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, March 17, 2014 01:09:39 AM Rafael J. Wysocki wrote: > On Sunday, March 16, 2014 02:08:16 PM Stephane Eranian wrote: > > Rafael, > > > > Thanks for the analysis. > > > > On Sun, Mar 16, 2014 at 12:55 PM, Borislav Petkov wrote: > > > On Sat, Mar 15, 2014 at 03:15:04PM +0100, Rafael J. Wysocki wrote: > > >> I've just gone throught this. > > > > > > Thanks. > > > > > >> So the problem is that we have the PNP "system" driver whose only purpose seems > > >> to be to reserve system resources so that the PCI layer doesn't assign them to > > >> new devices on hotplug (disclaimer: I didn't invent it, I only read the code and > > >> comments in there). > > >> > > >> It does that for ACPI device objects having the "PNP0C02" and "PNP0C01" IDs. > > > > > > Right, pnp 00:01 is PNP0C02. > > > > > >> Apparently, snb_uncore_imc_init_box() steps on a range already reserved by that > > >> driver on your box. And this doesn't seem to be a coincidence, because the ACPI > > >> device object in question probably *does* correspond to the memory controller > > >> that the uncore driver attempts to use. > > >> > > >> I'm not sure how to address that right now to be honest. Arguably, the PNP > > >> "system" driver should be replaced with something saner, but still the > > >> resources it claims need to be kept out of reach of the PCI's resource > > >> allocation code. > > > > > > Well, I'm only conjecturing here but there should be a way for the > > > uncore code to tell the PNP "system" driver to free this resource > > > because uncore is going to use it now. Or something to that effect. > > > > > I agree. The snb_uncore_imc() is making real (good) use of the device. > > It needs to own it. So we need a way to free the resource from the PNP > > system or a way to tell PNP need to grab it on systems with the > > snb_uncore_imc() support. Does that kind of API exist? > > > > Where do I look to prevent PNP from grabbing the IMC? > > drivers/pnp/system.c is the driver in question and system_pnp_probe() makes > the reservations via reserve_resources_of_dev(), so you'd need to modify that. > > I'm not sure what's the right way to go here, though. Boris, can you please sent the acpidump output from that machine? -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.