From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757507Ab3KNVWV (ORCPT ); Thu, 14 Nov 2013 16:22:21 -0500 Received: from mail-pd0-f180.google.com ([209.85.192.180]:40923 "EHLO mail-pd0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756160Ab3KNVWL (ORCPT ); Thu, 14 Nov 2013 16:22:11 -0500 From: Grant Likely Subject: Re: [PATCH v3 2/3] OF: Introduce DT overlay support. To: Pantelis Antoniou Cc: Rob Herring , Stephen Warren , Matt Porter , Koen Kooi , Alison Chaiken , Dinh Nguyen , Jan Lubbe , Alexander Sverdlin , Michael Stickel , Guenter Roeck , Dirk Behme , Alan Tull , Sascha Hauer , Michael Bohan , Ionut Nicu , Michal Simek , Matt Ranostay , Joel Becker , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: References: <1383923170-24914-1-git-send-email-panto@antoniou-consulting.com > <1383923170-24914-3-git-send-email-panto@antoniou-consulting.com> < 20131111184245.D569DC4234A@trevor.secretlab.ca> < ED51965C-6EC8-48AE-A59C-CD09FFD57731@antoniou-consulting.com> < 20131114013124.7DD0AC404DF@trevor.secretlab.ca> < E4922A5F-11B3-4167-91EF-C0D5F3F77D40@antoniou-consulting.com> Date: Fri, 15 Nov 2013 06:22:06 +0900 Message-Id: <20131114212206.EAD1BC402B4@trevor.secretlab.ca> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 14 Nov 2013 11:01:35 +0100, Pantelis Antoniou wrote: > On Nov 14, 2013, at 2:31 AM, Grant Likely wrote: > > On Tue, 12 Nov 2013 10:30:37 +0100, Pantelis Antoniou wrote: > >> On Nov 11, 2013, at 7:42 PM, Grant Likely wrote: > >>> On Fri, 8 Nov 2013 17:06:09 +0200, Pantelis Antoniou wrote: > >> I'm of the opinion that 'platform_device' shouldn't exist at all btw :) > >> Most of it's functionality can pretty easily be subsumed by device proper > >> and the world would be a better place :) > > > > I'm fine for merging some/all of the platform_device fields into struct > > device. There are a few things, like resources, which would probably be > > useful to have common on all struct device variants. However, > > platform_device is far more about matching drivers to devices. Even if > > all of platform_device went into struct device, there would still need > > to be the platform_bus_type as the collection point for the device > > drivers. > > > > We don't really need the resources structures on OF. That information is > present in OF format, which we can use to generate transient resources for > usage with the standard kernel interfaces. > > BTW, last time I checked resource handling was broken on release. > There are a few patches I sent out fixing it but they were probably ignored. Please send them again. They probably got lost. > >>> Can overlays interact in bad ways? If overlay 1 is installed before > >>> overlay 2, what happens if overlay 1 is removed? > >>> > >> > >> Yes, they can. It is not something easily fixed; the proper way would > >> be to calculate overlay intersection points and refuse to unload. > > > > I think this is important. If it cannot be solved immediately, then the > > kernel should enforce overlays always get removed in the reverse order > > that they were added. There may be use-cases that don't like it, but it > > is safe. > > OK, that makes sense. > > We are not talking about a global overlay stack though, we're talking about > an overlay stack for overlays that overlap. I'm actually talking about a global overlay stack. Otherwise you've still got the ever-increasing-phandles problem again. Cheers, g.