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 48512C43610 for ; Thu, 15 Nov 2018 17:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B41521780 for ; Thu, 15 Nov 2018 17:46:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B41521780 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.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 S2388868AbeKPDzG (ORCPT ); Thu, 15 Nov 2018 22:55:06 -0500 Received: from foss.arm.com ([217.140.101.70]:38760 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388808AbeKPDzF (ORCPT ); Thu, 15 Nov 2018 22:55:05 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C486780D; Thu, 15 Nov 2018 09:46:18 -0800 (PST) Received: from e107981-ln.cambridge.arm.com (e107981-ln.cambridge.arm.com [10.1.197.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id ADAD63F718; Thu, 15 Nov 2018 09:46:15 -0800 (PST) Date: Thu, 15 Nov 2018 17:46:08 +0000 From: Lorenzo Pieralisi To: Mika Westerberg Cc: Lukas Wunner , 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: <20181115174608.GA17691@e107981-ln.cambridge.arm.com> References: <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> <20181115121627.GA2500@lahna.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115121627.GA2500@lahna.fi.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) 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 02:16:27PM +0200, Mika Westerberg wrote: > 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? ;-) Do you really need to parse it if the dev->is_thunderbolt check is enough ? Thanks, Lorenzo