From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751637AbaDSL7r (ORCPT ); Sat, 19 Apr 2014 07:59:47 -0400 Received: from moutng.kundenserver.de ([212.227.126.131]:58652 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142AbaDSL7p (ORCPT ); Sat, 19 Apr 2014 07:59:45 -0400 From: Arnd Bergmann To: Daniel Mack Subject: Re: [PATCH v4 00/21] ARM: support for ICP DAS LP-8x4x (with dts) Date: Sat, 19 Apr 2014 13:59:35 +0200 User-Agent: KMail/1.12.2 (Linux/3.8.0-22-generic; KDE/4.3.2; x86_64; ; ) Cc: Sergei Ianovich , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Haojian Zhuang , "laurent.pinchart" , kernel@pengutronix.de References: <1387309071-22382-1-git-send-email-ynvich@gmail.com> <1397736755.16539.15.camel@host5.omatika.ru> <534FCA5D.1020606@zonque.org> In-Reply-To: <534FCA5D.1020606@zonque.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201404191359.36203.arnd@arndb.de> X-Provags-ID: V02:K0:4KSBmpMvIZO4tz+Zag5PcCEccdv3UpJp59dvR8qT5lM MLosfDYbG0ZYxvzYqiqZmhzeZ4lskaQYH79F6nQtXbZIdcCr/c HxvCoLW+cAh4TNrnqgIWyinETJ08BPcawcyaO8mXA2/hNLOygL Vvw+gPXII1lSYvaRxHdXk1PpYP4bN/6alaWjOskOw3dnmQMKVA s3LxmY9LJMExc7bQzrnihbOIQfR1yZzdzuFf1mieQ+2z3y710k /odM+dTdHKM+0WnhRnNRHFecHZcNU8VY/0GNh6IS46zN0gMo8v 24sv8D6GGuO2g51nVLrbYzxyH4S+8xfzeIxE8ozJ5+mfpuTJ/Z H8peECZTuI5y/gfPn0Kdk7n8x9tbGkozEjjkViPvi Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 17 April 2014, Daniel Mack wrote: > On 04/17/2014 02:12 PM, Sergei Ianovich wrote: > > On Thu, 2014-04-17 at 12:38 +0200, Daniel Mack wrote > > I have all the > > reasons to believe, that LP-8x4x support would already have be merged, > > if I didn't try to use DT. > > That might be, but that's not the point. We want progress here, and that > means we occasionally have to get rid of legacy. In most cases, I would strongly support that statement. However, for PXA in particular, my opinion is that progress is not the highest priority as I see no realistic hope of converting all the existing machines over to use DT and change the platform to "multiplatform" support. Anything more modern than PXA I hope we can eventually get at least done for multiplatform, same for a few of the older and simpler platforms. Then again, I'm certainly not stopping you from trying to use add modern platforms to PXA. One of the ideas I had earlier was to extend mach-mmp enough to run any fully DT-enabled PXA machines and leave mach-pxa for the old ATAGS support and stuff like the legacy DMA support. However, I don't think we should try that as long as mach-mmp is lacking some essential DT support, e.g. for the clocks that were only partially converted to use the common clock framework. > > if so > > B. We need to thinks whether it's acceptable to kill support for video > > capture. > > We can't. As I said, for this particular driver, we can keep the old API > around. We can even make it depend on !CONFIG_DMA_ENGINE, so if anyone > actually wants to use it with DT-enabled boards, we finally have a user > and things can be fixed up. Similar for other drivers we can't test > ourselves. Sounds good to me. > > In short: > > > > if (A && B) > > we drop old DMA > > else > > we take my patch #7 > > If A works, there's no need to for patch #7, right? If A doesn't work, > we have to check why and fix it. > > Arnd, any oppinion on this? No strong opinion, I wouldn't object patch #7 if there is a strong reason to not use the dmaengine driver for PXA like I would object doing it for MMP. Then again, I see that you and recently also Laurent are driving a lot of good work on PXA, and if neither the arm-soc maintainers nor the three maintainers listed for mach-pxa have a strong opinion, I'd rather leave it up to your judgement. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Sat, 19 Apr 2014 13:59:35 +0200 Subject: [PATCH v4 00/21] ARM: support for ICP DAS LP-8x4x (with dts) In-Reply-To: <534FCA5D.1020606@zonque.org> References: <1387309071-22382-1-git-send-email-ynvich@gmail.com> <1397736755.16539.15.camel@host5.omatika.ru> <534FCA5D.1020606@zonque.org> Message-ID: <201404191359.36203.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thursday 17 April 2014, Daniel Mack wrote: > On 04/17/2014 02:12 PM, Sergei Ianovich wrote: > > On Thu, 2014-04-17 at 12:38 +0200, Daniel Mack wrote > > I have all the > > reasons to believe, that LP-8x4x support would already have be merged, > > if I didn't try to use DT. > > That might be, but that's not the point. We want progress here, and that > means we occasionally have to get rid of legacy. In most cases, I would strongly support that statement. However, for PXA in particular, my opinion is that progress is not the highest priority as I see no realistic hope of converting all the existing machines over to use DT and change the platform to "multiplatform" support. Anything more modern than PXA I hope we can eventually get at least done for multiplatform, same for a few of the older and simpler platforms. Then again, I'm certainly not stopping you from trying to use add modern platforms to PXA. One of the ideas I had earlier was to extend mach-mmp enough to run any fully DT-enabled PXA machines and leave mach-pxa for the old ATAGS support and stuff like the legacy DMA support. However, I don't think we should try that as long as mach-mmp is lacking some essential DT support, e.g. for the clocks that were only partially converted to use the common clock framework. > > if so > > B. We need to thinks whether it's acceptable to kill support for video > > capture. > > We can't. As I said, for this particular driver, we can keep the old API > around. We can even make it depend on !CONFIG_DMA_ENGINE, so if anyone > actually wants to use it with DT-enabled boards, we finally have a user > and things can be fixed up. Similar for other drivers we can't test > ourselves. Sounds good to me. > > In short: > > > > if (A && B) > > we drop old DMA > > else > > we take my patch #7 > > If A works, there's no need to for patch #7, right? If A doesn't work, > we have to check why and fix it. > > Arnd, any oppinion on this? No strong opinion, I wouldn't object patch #7 if there is a strong reason to not use the dmaengine driver for PXA like I would object doing it for MMP. Then again, I see that you and recently also Laurent are driving a lot of good work on PXA, and if neither the arm-soc maintainers nor the three maintainers listed for mach-pxa have a strong opinion, I'd rather leave it up to your judgement. Arnd