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=-6.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 44AA3C433E6 for ; Tue, 12 Jan 2021 22:59:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17C5823122 for ; Tue, 12 Jan 2021 22:59:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394945AbhALW6p (ORCPT ); Tue, 12 Jan 2021 17:58:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:35212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394889AbhALW6o (ORCPT ); Tue, 12 Jan 2021 17:58:44 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 71E932311F; Tue, 12 Jan 2021 22:58:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610492283; bh=TD2GgmyopcuNlUr3NT6X/nzg/uWon7PfAk17CArwiDk=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=dDg9mEAFMl31vH2EkotpUo8k4q99uFjs5eZ4DGaOmt5niUL4XgQwfm9wBp6phDv8E /WcWAQlj94Sz5IsHG25hAAdzllLG9ixRhxXuwClPdHfyEt3mRpMabDlN9slIDzYpBX 6+n10U4bxwg64LIR3R5RM3snIn5PhqsDyxBKJ65pYenxCrmlBrX+wmRcN+8zgFoGz1 8+4/aL5YaE4zROIwezt63hdSjW/uv0Jd+hcIcjoxAJ2SD8cI7n2+abF9yRn/QYkIt5 SGKWhrlkNk0GXIHhFOhIDUuNyTC6NPR43voH9MnCJvuAegJlyB6v4CPazZQWto2pl+ C0rBtndHOQLrg== Date: Tue, 12 Jan 2021 16:58:02 -0600 From: Bjorn Helgaas To: Michael Walle Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org, Bjorn Helgaas , Jesse Brandeburg , Tony Nguyen , Paul Menzel Subject: Re: [PATCH v2] PCI: Fix Intel i210 by avoiding overlapping of BARs Message-ID: <20210112225802.GA1859984@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <642eb96b495f5ad7d2d14410fedcd1ad@walle.cc> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Sat, Jan 09, 2021 at 07:31:46PM +0100, Michael Walle wrote: > Hi Bjorn, > > Am 2021-01-08 22:20, schrieb Bjorn Helgaas: > > On Wed, Dec 30, 2020 at 07:53:17PM +0100, Michael Walle wrote: > > > The Intel i210 doesn't work if the Expansion ROM BAR overlaps with > > > another BAR. Networking won't work at all and once a packet is sent > > > the > > > netdev watchdog will bite: > > > > 1) Is this a regression? It sounds like you don't know for sure > > because earlier kernels don't support your platform. > > Whats the background of the question? The board is offially supported > since 5.8. I doubt that the code responsible to not touch the ExpROM > BAR in pci_std_update_resource() were recently changed/added; the > comment refers to a mail from 2005. So no I don't think it is a > regression per se. Just asking because it affects the urgency. If we added a regression during the v5.11 merge window, we'd try hard to fix it before v5.11-final. But it sounds like the problem has been there a long time, so a fix could wait until v5.12. > It is just that some combination of hardware and firmware will program > the BARs in away so that this bug is triggered. And chances of this > happing are very unlikely. > > Do we agree that it should be irrelevant how the firmware programs and > enables the BARs in this case? I.e. you could "fix" u-boot to match the > way linux will assign addresses to the BARs. But that would just work > around the real issue here. IMO. I agree, Linux should work correctly regardless of how firmware programmed the BARs. > > 2) Can you open a bugzilla at https://bugzilla.kernel.org and attach > > the complete dmesg and "sudo lspci -vv" output? I want to see whether > > Linux is assigning something incorrectly or this is a consequence of > > some firmware initialization. > > Sure, but you wouldn't even see the error with "lspci -vv" because > lspci will just show the mapping linux assigned to it. But not whats > written to the actual BAR for the PCI card. I'll also include a > "lspci -xx". I've enabled CONFIG_PCI_DEBUG, too. > > https://bugzilla.kernel.org/show_bug.cgi?id=211105 > > > 3) If the Intel i210 is defective in how it handles an Expansion ROM > > that overlaps another BAR, a quirk might be the right fix. But my > > guess is the device is working correctly per spec and there's > > something wrong in how firmware/Linux is assigning things. That would > > mean we need a more generic fix that's not a quirk and not tied to the > > Intel i210. > > Agreed, but as you already stated (and I've also found that in the PCI > spec) the Expansion ROM address decoder can be shared by the other BARs > and it shouldn't matter as long as the ExpROM BAR is disabled, which is > the case here. My point is just that if this could theoretically affect devices other than the i210, the fix should not be an i210-specific quirk. I'll assume this is a general problem and wait for a generic PCI core solution unless it's i210-specific. Bjorn