From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTP id A155998F for ; Mon, 5 May 2014 11:05:28 +0000 (UTC) Received: from v094114.home.net.pl (v094114.home.net.pl [79.96.170.134]) by smtp1.linuxfoundation.org (Postfix) with SMTP id 724F920214 for ; Mon, 5 May 2014 11:05:26 +0000 (UTC) From: "Rafael J. Wysocki" To: Pantelis Antoniou Date: Mon, 05 May 2014 13:22:02 +0200 Message-ID: <7305827.ZucddAVROE@vostro.rjw.lan> In-Reply-To: <93AA3E28-F354-42D8-B8F2-F2517493CE23@antoniou-consulting.com> References: <7701777.LWanFdz802@vostro.rjw.lan> <93AA3E28-F354-42D8-B8F2-F2517493CE23@antoniou-consulting.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Cc: "dvhart@dvhart.com" , ksummit-discuss@lists.linuxfoundation.org, Georgi Vlaev , "Rafael J. Wysocki" , Greg Kroah-Hartman Subject: Re: [Ksummit-discuss] [TECH TOPIC] Driver model/resources, ACPI, DT, etc (sigh) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sunday, May 04, 2014 07:44:27 PM Pantelis Antoniou wrote: > Hi Rafael, > > On May 4, 2014, at 3:02 PM, Rafael J. Wysocki wrote: > > > Hi, > > > > On Sunday, May 04, 2014 10:27:59 AM Guenter Roeck wrote: > >> On 05/04/2014 10:18 AM, Olof Johansson wrote: > > > > [cut] > > > >>> I think it's very optimistic to assume that there will ever be a common > >>> solution for both ends of the spectrum (embedded - enterprise), but we > >>> should make sure we can stay sane and not have more solutions than we need > >>> in parallel, and that things will work together where there is overlap. > >>> > >> We (Juniper) are moving towards a partial conversion from ACPI to DT, pretty > >> much just enough to let us work with DT overlays on X86. If there is interest > >> to discuss this, it might make sense to invite Pantelis Antoniou and possibly > >> Georgi Vlaev, since both are instrumental to making it work. > > > > I actually wonder how you are going to handle things like references from > > a DT overlay to ACPI device objects in the namespace (like various things > > controllers etc). > > > > At the moment we got dynamic PCI DT node creation; i.e. the PCI bus(es) is probed > and the platform's pci bios creates DT nodes; PCI nodes that already defined do not > get created from scratch, rather DT properties are appended to them. Well, what you're describing is not a DT overlay on top of an otherwise ACPI-based system. It is DT support for PCI. > It is not a whole-sale conversion (yet), but it seems to work find as a target for > DT overlays. > > All this is on vanilla x86-64 btw, with very small fixes to get booted using an DT blob. > > So far we didn't have to deal with ACPI device objects; perhaps it will be required > for when we tackle pure platform devices. But TBH it doesn't seem that difficult. In the context of DT-over-ACPI overlays it doesn't matter what devices you're considering. The problem is the translation of phandles into ACPI device object pointers (paths) or the other way around. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.