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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 3F1E0C04EBF for ; Thu, 15 Nov 2018 12:16:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F716223CB for ; Thu, 15 Nov 2018 12:16:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F716223CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com 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 S2388187AbeKOWYL (ORCPT ); Thu, 15 Nov 2018 17:24:11 -0500 Received: from mga06.intel.com ([134.134.136.31]:4219 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729155AbeKOWYK (ORCPT ); Thu, 15 Nov 2018 17:24:10 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Nov 2018 04:16:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,236,1539673200"; d="scan'208";a="249920703" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by orsmga004.jf.intel.com with SMTP; 15 Nov 2018 04:16:28 -0800 Received: by lahna (sSMTP sendmail emulation); Thu, 15 Nov 2018 14:16:27 +0200 Date: Thu, 15 Nov 2018 14:16:27 +0200 From: Mika Westerberg To: Lukas Wunner Cc: Lorenzo Pieralisi , iommu@lists.linux-foundation.org, Joerg Roedel , David Woodhouse , Lu Baolu , Ashok Raj , Bjorn Helgaas , "Rafael J. Wysocki" , Jacob jun Pan , Andreas Noever , Michael Jamet , Yehezkel Bernat , Christian Kellner , Mario.Limonciello@dell.com, Anthony Wong , linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] PCI / ACPI: Identify external PCI devices Message-ID: <20181115121627.GA2500@lahna.fi.intel.com> References: <20181112160628.86620-1-mika.westerberg@linux.intel.com> <20181112160628.86620-2-mika.westerberg@linux.intel.com> <20181112180203.lx72gjfplb6xlur7@wunner.de> <20181113105636.GB11202@e107981-ln.cambridge.arm.com> <20181113112700.GT2500@lahna.fi.intel.com> <20181113114527.GA12821@e107981-ln.cambridge.arm.com> <20181115102239.GU2500@lahna.fi.intel.com> <20181115111356.GA599@e107981-ln.cambridge.arm.com> <20181115113737.GW2500@lahna.fi.intel.com> <20181115120736.pscly6zwd3k2tvd2@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115120736.pscly6zwd3k2tvd2@wunner.de> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 15, 2018 at 01:07:36PM +0100, Lukas Wunner wrote: > On Thu, Nov 15, 2018 at 01:37:37PM +0200, Mika Westerberg wrote: > > On Thu, Nov 15, 2018 at 11:13:56AM +0000, Lorenzo Pieralisi wrote: > > > I have strong objections to the way these bindings have been forced upon > > > everybody; if that's the way *generic* ACPI bindings are specified I > > > wonder why there still exists an ACPI specification and related working > > > group. > > > > > > I personally (but that's Bjorn and Rafael choice) think that this is > > > not a change that belongs in PCI core, ACPI bindings are ill-defined > > > and device tree bindings are non-existing. > > > > Any idea where should I put it then? These systems are already out there > > and we need to support them one way or another. > > I suppose those are all Thunderbolt, so could be handled by the > existing ->is_thunderbolt bit? > > It was said in this thread that ->is_external is more generic in > that it could also be used on PCIe slots, however that use case > doesn't appear to lend itself to the "plug in while laptop owner > is getting coffee" attack. To access PCIe slots on a server you > normally need access to a data center. On a desktop, you usually > have to open the case, by which time the coffee may already have > been fetched. So frankly the binding seems a bit over-engineered > to me and yet another thing that BIOS writers may get wrong. I would not say it should include PCIe slots but there are other cables that carry PCIe and I was thinking we could make it to support those as well. I have no problem using is_thunderbolt here, though if we don't want to support non-Thunderbolt external devices this way. However, the question here is more that where I should put the _DSD parsing code if it is not suitable to be placed inside PCI/ACPI core as I've done in this patch? ;-)