From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [RFC 00/15] ACPI graph support Date: Thu, 6 Oct 2016 14:19:22 +0300 Message-ID: <20161006111922.GI30800@lahna.fi.intel.com> References: <1475621148-21427-1-git-send-email-sakari.ailus@linux.intel.com> <20161005092215.GA20248@red-moon> <20161005114129.GI1765@lahna.fi.intel.com> <20161005150641.GA22282@red-moon> <20161005153229.GO1765@lahna.fi.intel.com> <20161005161800.GA22433@red-moon> <20161006085703.GA22776@red-moon> <20161006091133.GF30800@lahna.fi.intel.com> <20161006095739.GA22984@red-moon> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga04.intel.com ([192.55.52.120]:41609 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755846AbcJFL2N (ORCPT ); Thu, 6 Oct 2016 07:28:13 -0400 Content-Disposition: inline In-Reply-To: <20161006095739.GA22984@red-moon> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lorenzo Pieralisi Cc: "Rafael J. Wysocki" , Sakari Ailus , ACPI Devel Maling List , Mark Rutland , Mark Brown , Rob Herring , Al Stone On Thu, Oct 06, 2016 at 10:57:39AM +0100, Lorenzo Pieralisi wrote: > On Thu, Oct 06, 2016 at 12:11:33PM +0300, Mika Westerberg wrote: > > On Thu, Oct 06, 2016 at 09:57:03AM +0100, Lorenzo Pieralisi wrote: > > > I am trying to understand why x86 wants to do this, please understand > > > our point of view too, we do not want to block progress we want to > > > prevent a mess. > > > > One reason is that we have boards like Joule where developers are > > allowed to connect different peripherals using buses such as I2C and SPI > > where there is no native enumeration mechanism. This includes camera > > sensors and related so there needs to be a way for a developer to > > describe this in ACPI. Just as can be done when using ARM and DT. > > I am sorry I think we are at loggerheads on this. If you need a DT boot > with a DT, I could have converted all the ACPI tables to DT nodes on > ARM64 if I followed your reasoning (because we could not boot with ACPI > till relatively recently), we did not do it because ACPI and DT are > different specifications, incompatible with one another and governed by > different entities in a *very* different way. I don't need a DT, I need that my existing firmware (in this case BIOS) can describe camera device(s) and the OS can take advantage of this, preferably with minimal changes to the drivers. Currently there is no way in ACPI specification to do that. > You are saying that just re-using leaf nodes properties (well, it > is not just leaf-nodes properties any longer, is it ?) is just > fine; Yes. Not sure where this remote-endpoint thing belongs, to be honest. It is used inside V4L2 to determine which parts of the system make up a camera device so in that sense it is "leaf-node" property but it is not limited to just V4L2. > I(We) am not convinced, time will tell. In the interim > please notify the respective subsystems maintainers and DT people > of this patch intentions, again I hope I am not asking too much. I think Sakari already did that for V4L2. Next version will include all the relevant mailing lists.