From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6A22C4708A for ; Thu, 27 May 2021 09:32:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8847C61415 for ; Thu, 27 May 2021 09:32:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235720AbhE0Jdl (ORCPT ); Thu, 27 May 2021 05:33:41 -0400 Received: from foss.arm.com ([217.140.110.172]:54734 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235820AbhE0Jdk (ORCPT ); Thu, 27 May 2021 05:33:40 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 66FED13A1; Thu, 27 May 2021 02:32:07 -0700 (PDT) Received: from lpieralisi (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 13B963F73D; Thu, 27 May 2021 02:32:05 -0700 (PDT) Date: Thu, 27 May 2021 10:32:00 +0100 From: Lorenzo Pieralisi To: Will Deacon , Bjorn Helgaas Cc: Maximilian Luz , "Rafael J. Wysocki" , Len Brown , Catalin Marinas , linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] Revert "arm64: PCI: Exclude ACPI "consumer" resources from host bridge windows" Message-ID: <20210527093200.GA16444@lpieralisi> References: <20210510234020.1330087-1-luzmaximilian@gmail.com> <20210526205836.GA20320@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210526205836.GA20320@willie-the-truck> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, May 26, 2021 at 09:58:36PM +0100, Will Deacon wrote: > On Tue, May 11, 2021 at 01:40:20AM +0200, Maximilian Luz wrote: > > The Microsoft Surface Pro X has host bridges defined as > > > > Name (_HID, EisaId ("PNP0A08") /* PCI Express Bus */) // _HID: Hardware ID > > Name (_CID, EisaId ("PNP0A03") /* PCI Bus */) // _CID: Compatible ID > > > > Method (_CRS, 0, NotSerialized) // _CRS: Current Resource Settings > > { > > Name (RBUF, ResourceTemplate () > > { > > Memory32Fixed (ReadWrite, > > 0x60200000, // Address Base > > 0x01DF0000, // Address Length > > ) > > WordBusNumber (ResourceProducer, MinFixed, MaxFixed, PosDecode, > > 0x0000, // Granularity > > 0x0000, // Range Minimum > > 0x0001, // Range Maximum > > 0x0000, // Translation Offset > > 0x0002, // Length > > ,, ) > > }) > > Return (RBUF) /* \_SB_.PCI0._CRS.RBUF */ > > } > > > > meaning that the memory resources aren't (explicitly) defined as > > "producers", i.e. host bridge windows. > > > > Commit 8fd4391ee717 ("arm64: PCI: Exclude ACPI "consumer" resources from > > host bridge windows") introduced a check that removes such resources, > > causing BAR allocation failures later on: > > > > [ 0.150731] pci 0002:00:00.0: BAR 14: no space for [mem size 0x00100000] > > [ 0.150744] pci 0002:00:00.0: BAR 14: failed to assign [mem size 0x00100000] > > [ 0.150758] pci 0002:01:00.0: BAR 0: no space for [mem size 0x00004000 64bit] > > [ 0.150769] pci 0002:01:00.0: BAR 0: failed to assign [mem size 0x00004000 64bit] > > > > This eventually prevents the PCIe NVME drive from being accessible. > > > > On x86 we already skip the check for producer/window due to some history > > with negligent firmware. It seems that Microsoft is intent on continuing > > that history on their ARM devices, so let's drop that check here too. > > > > Signed-off-by: Maximilian Luz > > --- > > > > Please note: I am not sure if this is the right way to fix that, e.g. I > > don't know if any additional checks like on IA64 or x86 might be > > required instead, or if this might break things on other devices. So > > please consider this more as a bug report rather than a fix. > > > > Apologies for the re-send, I seem to have unintentionally added a blank > > line before the subject. > > > > --- > > arch/arm64/kernel/pci.c | 14 -------------- > > 1 file changed, 14 deletions(-) > > Adding Lorenzo to cc, as he'll have a much better idea about this than me. > > This is: > > https://lore.kernel.org/r/20210510234020.1330087-1-luzmaximilian@gmail.com Sigh. We can't apply this patch since it would trigger regressions on other platforms (IIUC the root complex registers would end up in the host bridge memory windows). I am not keen on reverting commit 8fd4391ee717 because it does the right thing. I think this requires a quirk and immediate reporting to Microsoft. Bjorn, what are your thoughts on this ? Thanks, Lorenzo