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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 E5A58C43381 for ; Thu, 14 Feb 2019 07:01:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB4AB222B6 for ; Thu, 14 Feb 2019 07:01:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405944AbfBNHBD (ORCPT ); Thu, 14 Feb 2019 02:01:03 -0500 Received: from bmailout2.hostsharing.net ([83.223.90.240]:42485 "EHLO bmailout2.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405695AbfBNHBD (ORCPT ); Thu, 14 Feb 2019 02:01:03 -0500 Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.hostsharing.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (not verified)) by bmailout2.hostsharing.net (Postfix) with ESMTPS id 982322800B488; Thu, 14 Feb 2019 08:01:00 +0100 (CET) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 5262457CE2; Thu, 14 Feb 2019 08:01:00 +0100 (CET) Date: Thu, 14 Feb 2019 08:01:00 +0100 From: Lukas Wunner To: Alex_Gagniuc@Dellteam.com Cc: mr.nuke.me@gmail.com, bhelgaas@google.com, Austin.Bolen@dell.com, keith.busch@intel.com, Shyam.Iyer@dell.com, gustavo@embeddedor.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI: pciehp: Do not turn off slot if presence comes up after link Message-ID: <20190214070100.kvikmkkcrp2d32sm@wunner.de> References: <20190205210701.25387-1-mr.nuke.me@gmail.com> <20190209115849.244u67h7wmn3eb7o@wunner.de> <52afa1c45f684dbda6a8771b65583a22@ausx13mps321.AMER.DELL.COM> <20190212083031.2no7mzn5xug7nba3@wunner.de> <20190213083632.GA3387@wunner.de> <205e0fd9995a4f2b80ab370a974b6628@ausx13mps321.AMER.DELL.COM> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <205e0fd9995a4f2b80ab370a974b6628@ausx13mps321.AMER.DELL.COM> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Feb 13, 2019 at 06:55:46PM +0000, Alex_Gagniuc@Dellteam.com wrote: > On 2/13/19 2:36 AM, Lukas Wunner wrote: > > > (*) A bit hypothetical: There is no hardware yet implementing the ECN. > > > > Hm, this contradicts Austin Bolen's e-mail of Jan 25 that "Yes, this > > platform disables in-band presence" (when asked whether your host > > controller already adheres to the ECN). > > Both statements are true. The hardware does indeed disable in-band > presence, in a rudimentary way that is not compliant with the ECN -- it > doesn't implement the bits required by the ECN. Ugh, can a BIOS update make those machines compliant to the ECN or do we need a quirk specifically for them? > > Polling PDS in > > pcie_wait_for_link() or disabling either PDC or DLLSC if in-band presence > > is disabled seems simpler to reason about. > > pcie_wait_for_link() is generic PCIe layer. I don't think mixing hotplug > concepts is a good layering violation. The function used to live in pciehp_hpc.c, but commits 9f5a70f18c58 and f0157160b359 moved it to generic code to allow code sharing with the DPC driver. That's the only reason it's in generic code AFAICS. > >> in-band PD disable (what's a good acronym for that, BTW?) > > > > I don't know, maybe inband_presence_disabled? > > PCI_EXP_SLTCAP2_IBPD ? Yes, something like that. It should match the spec, which I have no access to. Thanks, Lukas