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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 14E9AC35254 for ; Wed, 5 Feb 2020 12:15:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD1EC217F4 for ; Wed, 5 Feb 2020 12:15:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726748AbgBEMPb (ORCPT ); Wed, 5 Feb 2020 07:15:31 -0500 Received: from mx2.suse.de ([195.135.220.15]:47212 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726575AbgBEMPb (ORCPT ); Wed, 5 Feb 2020 07:15:31 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 81B68ACC6; Wed, 5 Feb 2020 12:15:29 +0000 (UTC) Message-ID: <1580904900.9756.9.camel@suse.com> Subject: Re: system generating an NMI due to 80696f991424d ("PCI: pciehp: Tolerate Presence Detect hardwired to zero") From: Oliver Neukum To: Lukas Wunner Cc: David Yang , Rajat Jain , Ashok Raj , linux-pci@vger.kernel.org, Stuart Hayes Date: Wed, 05 Feb 2020 13:15:00 +0100 In-Reply-To: <20200116053500.chp4rsbeflg3qrdr@wunner.de> References: <1579083986.15925.31.camel@suse.com> <20200115112429.yrj5v2zhvxkoupbw@wunner.de> <20200116053500.chp4rsbeflg3qrdr@wunner.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Am Donnerstag, den 16.01.2020, 06:35 +0100 schrieb Lukas Wunner: > [cc += Stuart] > > On Wed, Jan 15, 2020 at 12:24:29PM +0100, Lukas Wunner wrote: > > On Wed, Jan 15, 2020 at 11:26:26AM +0100, Oliver Neukum wrote: > > > I got a bug report about some systems generating an NMI and > > > subsequently crashing bisected down to 80696f991424d. > > > Apparently these systems do not react well to __pciehp_enable_slot > > > while no card is present. Restoring the check to __pciehp_enable_slot() > > > removed in 80696f991424d makes the current kernels work. > > > > That's odd, these systems must be setting the Data Link Layer Link Active > > bit in the Link Status Register even though no card is present. > > Recent PCIe versions allow turning off in-band presence detect, in which > case the DLLLA bit can be set even though Presence Detect is not set. > You may be dealing with one of those systems but without full dmesg > and lspci output this is just an educated guess. > > A series was submitted by Dell last year to support disabling in-band > presence detect, but it hasn't been merged yet by Bjorn: > > https://lore.kernel.org/linux-pci/20191025190047.38130-1-stuart.w.hayes@gmail.com/ > > You may want to try if that series helps. Hi, it has been tested and it does the job. May I ask whether you could ack it or propose necessary changes, so that we can proceed? Regards Oliver