From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752486AbaKKXjs (ORCPT ); Tue, 11 Nov 2014 18:39:48 -0500 Received: from avon.wwwdotorg.org ([70.85.31.133]:38020 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752028AbaKKXjq (ORCPT ); Tue, 11 Nov 2014 18:39:46 -0500 Message-ID: <54629E4A.7050201@wwwdotorg.org> Date: Tue, 11 Nov 2014 16:39:54 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Olof Johansson , Thierry Reding CC: Alexandre Courbot , "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , gregkh@linux-foundation.org, Laxman Dewangan Subject: Re: [PATCH] ARM: dts: tegra: move serial aliases to per-board References: <1415738970-7963-1-git-send-email-olof@lixom.net> <54627C1F.9050200@wwwdotorg.org> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/11/2014 03:45 PM, Olof Johansson wrote: > [again in plain text mode. Sigh] > > > On Tue, Nov 11, 2014 at 1:14 PM, Stephen Warren wrote: >> On 11/11/2014 01:49 PM, Olof Johansson wrote: >>> >>> There are general changes pending to make the /aliases/serial* entries >>> number the serial ports on the system. On tegra, so far the ports have >>> been >>> just numbered dynamically as they are configured so that makes them >>> change. >>> >>> To avoid this, add specific aliases per board to keep the old numbers. >>> This >>> allows us to change the numbering by default on future SoCs while keeping >>> the >>> numbering on existing boards. >> >> >> This change seems mostly OK to me. FWIW though, I had suggested this >> approach when the UART aliases were first added, and Laxman disagreed with >> it. See commit b6551bb933f9 "ARM: tegra: dts: add aliases and DMA requestor >> for serial controller", and its discussion: >> https://lkml.org/lkml/2012/12/25/4. I've CC'd Laxman in case he still >> objects. >> >>> Signed-off-by: Olof Johansson >>> --- >>> >>> Stephen/Thierry/Alex, as noticed this week we really should try to get >>> this in before the 3.19 merge window so that the global aliases change >>> can happen there without regression. >> >> >> How did we resolve the issue that patch causes with old DTs; namely that it >> causes a change in behaviour for those old DTs? On IRC, I'd wondered whether >> we should set a flag so the kernel ignored aliases for boards containing >> currently upstreamed Tegra SoCs so that issue wouldn't occur. If we did >> that, we wouldn't need this patch. > > Another way could be to remove aliases from the kernel side during > booting if they're found. Anyway, feel free to send a patch to do that > if that's your preference. That would work too. I'll let Thierry make the call re: whether it's important to support old DTs with the current aliase content without a change in device names when booted on a newer kernel. If not, as I mentioned, I'm fine with this patch.