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=-6.0 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 E51EBC433ED for ; Thu, 8 Apr 2021 17:27:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A52726113A for ; Thu, 8 Apr 2021 17:27:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232632AbhDHR2B (ORCPT ); Thu, 8 Apr 2021 13:28:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:55806 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232599AbhDHR2B (ORCPT ); Thu, 8 Apr 2021 13:28:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5092861131; Thu, 8 Apr 2021 17:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617902869; bh=wruduVdkbEbjN2mkVIAUSClY/ZLVAdEhtioJoWM82c8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=CqdEGb/8ql8gxFI9ZAxHjCSp2KJOBGLddZcJljSWmiyITjK1b+lXL010kJBb7WK1+ Y5gRpFGSaqFA4yEgLTp7P9DHY5j4qL4R6AikY8C0qGbh9Hg3R4YsvEJyhaH5r8kG/E hmZpM91u/oLi5pc0NE/y13EN55Bq5CXkz7xhLoR8t0ds1N6l02Z8ebDAO4Ujeh0E5S SC5omn30dv5VmmWpjgQpw31bylwLGQY+9bsku2FVXVWHAwpARmWhpMgZz8FutCqlt5 1iB98o3V7gU5X2MuDzCCxhy+OlP8gdMBWQJYdq0ieMbOoS5mCnbX3y4Gg3JRWXFcUf Wehm+KVBxoV1Q== Date: Thu, 8 Apr 2021 12:27:47 -0500 From: Bjorn Helgaas To: Arun Easi Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, Girish Basrur , Quinn Tran Subject: Re: [PATCH 1/1] PCI/VPD: Fix blocking of VPD data in lspci for QLogic 1077:2261 Message-ID: <20210408172747.GA1940414@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Apr 07, 2021 at 03:57:32PM -0700, Arun Easi wrote: > On Wed, 7 Apr 2021, 3:13pm, Bjorn Helgaas wrote: > > > On Wed, Mar 03, 2021 at 02:42:50PM -0800, Arun Easi wrote: > > > "lspci -vvv" for Qlogic Fibre Channel HBA 1077:2261 displays > > > "Vital Product Data" as "Not readable" today and thus preventing > > > customers from getting relevant HBA information. Fix it by removing > > > the blacklist quirk. > > > > > > The VPD quirk was added by [0] to avoid a system NMI; this issue has > > > been long fixed in the HBA firmware. In addition, PCI also has changes > > > to check the VPD size [1], so this quirk can be reverted now regardless > > > of a firmware update. > > > > This is not a very convincing argument yet since 104daa71b396 ("PCI: > > Determine actual VPD size on first access") appeared in v4.6 and > > 0d5370d1d852 ("PCI: Prevent VPD access for QLogic ISP2722") appeared > > in v4.11. > > > > If 104daa71b396 really fixed the problem, why did we need > > 0d5370d1d852? > > True, 0d5370d1d852 was not really neeeded for 104daa71b396 and newer > kernels; my theory is that when Ethan Z. ran the tests, he was using an > older (older than 104daa71b396) kernel, but by the time the blacklisting > was put in place, the kernel already had the fix that made the > blacklisting unnecessary. > > More of my investigation details explained here: > https://lore.kernel.org/linux-pci/alpine.LRH.2.21.9999.2012161641230.28924@irv1user01.caveonetworks.com/ > > A quick summary of which is that, when Ethan reported the crash stack, it > had pci_vpd_pci22* calls which is seen only in older kernels. Though > 104daa71b396 too had those calls, it was very close to the commit that > renamed those calls (f1cd93f9aabe) -- and I theorized Ethan probably was > not running a kernel between 104daa71b396 and f1cd93f9aabe (only 3 > commits (drivers/pci/) away). We should put the outline of this theory in the commit log for the benefit of future readers who have the same question I did. Bjorn