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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 59445C46470 for ; Tue, 7 Aug 2018 19:44:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 181862172B for ; Tue, 7 Aug 2018 19:44:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 181862172B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390586AbeHGWAr (ORCPT ); Tue, 7 Aug 2018 18:00:47 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:49524 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390006AbeHGWAq (ORCPT ); Tue, 7 Aug 2018 18:00:46 -0400 Received: from localhost (71-36-117-41.ptld.qwest.net [71.36.117.41]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 69B1B10864B62; Tue, 7 Aug 2018 12:44:49 -0700 (PDT) Date: Tue, 07 Aug 2018 12:44:48 -0700 (PDT) Message-Id: <20180807.124448.1502585319140215353.davem@davemloft.net> To: mr.nuke.me@gmail.com Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, jakub.kicinski@netronome.com, keith.busch@intel.com, alex_gagniuc@dellteam.com, austin_bolen@dell.com, shyam_iyer@dell.com, ariel.elior@cavium.com, everest-linux-l2@cavium.com, michael.chan@broadcom.com, ganeshgr@chelsio.com, jeffrey.t.kirsher@intel.com, tariqt@mellanox.com, saeedm@mellanox.com, leon@kernel.org, dirk.vandermerwe@netronome.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-rdma@vger.kernel.org, oss-drivers@netronome.com Subject: Re: [PATCH v6 1/9] PCI: Check for PCIe downtraining conditions From: David Miller In-Reply-To: <20180806232600.25694-1-mr.nuke.me@gmail.com> References: <20180806232600.25694-1-mr.nuke.me@gmail.com> X-Mailer: Mew version 6.7 on Emacs 26 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 07 Aug 2018 12:44:50 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexandru Gagniuc Date: Mon, 6 Aug 2018 18:25:35 -0500 > PCIe downtraining happens when both the device and PCIe port are > capable of a larger bus width or higher speed than negotiated. > Downtraining might be indicative of other problems in the system, and > identifying this from userspace is neither intuitive, nor > straightforward. > > The easiest way to detect this is with pcie_print_link_status(), > since the bottleneck is usually the link that is downtrained. It's not > a perfect solution, but it works extremely well in most cases. > > Signed-off-by: Alexandru Gagniuc Feel free to merge this entire series via the PCI tree. For the series: Acked-by: David S. Miller