From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755284AbaDQMMm (ORCPT ); Thu, 17 Apr 2014 08:12:42 -0400 Received: from mail-la0-f48.google.com ([209.85.215.48]:55635 "EHLO mail-la0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751942AbaDQMMl (ORCPT ); Thu, 17 Apr 2014 08:12:41 -0400 Message-ID: <1397736755.16539.15.camel@host5.omatika.ru> Subject: Re: [PATCH v4 00/21] ARM: support for ICP DAS LP-8x4x (with dts) From: Sergei Ianovich To: Daniel Mack Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Arnd Bergmann , Haojian Zhuang , "laurent.pinchart" , kernel@pengutronix.de Date: Thu, 17 Apr 2014 16:12:35 +0400 In-Reply-To: <534FAF30.1000101@zonque.org> References: <1387309071-22382-1-git-send-email-ynvich@gmail.com> <1397668411-27162-1-git-send-email-ynvich@gmail.com> <534EC04F.9010408@gmail.com> <610ed273-1e54-4d44-b523-cbe0d042cf48@email.android.com> <534FAF30.1000101@zonque.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.8.5-2+b3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-04-17 at 12:38 +0200, Daniel Mack wrote: > I spent some hours on this topic again now, and rebased and tested my > tree to 3.15-rc1. Pushed it here: > > https://github.com/zonque/linux/tree/pxa-dma-3.15 Great. > There's some overlap to the patches you sent, which I'll comment on > directly soon. > > I'm booting my board with pxa[23]xx.dtsi taken from my tree. > > Please, if you find some time, test this tree and see if you still see > the performance regression. Sure. > Ok, so how about this: > > 1. We keep the old API around, along with compat wrappers for existing > drivers until someone finally finds time to at least test the patches > that I can only compile-test myself. > > 2. For platforms that don't need those exotic drivers for devices that > nobody seems to be interested in, use DT and the pxa-mmp-dma driver, and > make sure it performs as well as the old implementation. > > 3. Do not add hacks for DT-compatability of existing drivers to make > them work with the old DMA implementation (like your patch #7). > > 4. For new drivers, don't add any compat code for the old DMA > implementation but soley rely on the new DMA framework. > > > > Does this sound suitable for you? No. I see no value in #3. There are obvious reasons to use DT whenever possible. #3 effectively blocks DT usage for new devices. I have all the reasons to believe, that LP-8x4x support would already have be merged, if I didn't try to use DT. My plan: A. We need to know whether the new DMA implementation performs on par with the old one. (I'm starting to check). if so B. We need to thinks whether it's acceptable to kill support for video capture. In short: if (A && B) we drop old DMA else we take my patch #7 From mboxrd@z Thu Jan 1 00:00:00 1970 From: ynvich@gmail.com (Sergei Ianovich) Date: Thu, 17 Apr 2014 16:12:35 +0400 Subject: [PATCH v4 00/21] ARM: support for ICP DAS LP-8x4x (with dts) In-Reply-To: <534FAF30.1000101@zonque.org> References: <1387309071-22382-1-git-send-email-ynvich@gmail.com> <1397668411-27162-1-git-send-email-ynvich@gmail.com> <534EC04F.9010408@gmail.com> <610ed273-1e54-4d44-b523-cbe0d042cf48@email.android.com> <534FAF30.1000101@zonque.org> Message-ID: <1397736755.16539.15.camel@host5.omatika.ru> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 2014-04-17 at 12:38 +0200, Daniel Mack wrote: > I spent some hours on this topic again now, and rebased and tested my > tree to 3.15-rc1. Pushed it here: > > https://github.com/zonque/linux/tree/pxa-dma-3.15 Great. > There's some overlap to the patches you sent, which I'll comment on > directly soon. > > I'm booting my board with pxa[23]xx.dtsi taken from my tree. > > Please, if you find some time, test this tree and see if you still see > the performance regression. Sure. > Ok, so how about this: > > 1. We keep the old API around, along with compat wrappers for existing > drivers until someone finally finds time to at least test the patches > that I can only compile-test myself. > > 2. For platforms that don't need those exotic drivers for devices that > nobody seems to be interested in, use DT and the pxa-mmp-dma driver, and > make sure it performs as well as the old implementation. > > 3. Do not add hacks for DT-compatability of existing drivers to make > them work with the old DMA implementation (like your patch #7). > > 4. For new drivers, don't add any compat code for the old DMA > implementation but soley rely on the new DMA framework. > > > > Does this sound suitable for you? No. I see no value in #3. There are obvious reasons to use DT whenever possible. #3 effectively blocks DT usage for new devices. I have all the reasons to believe, that LP-8x4x support would already have be merged, if I didn't try to use DT. My plan: A. We need to know whether the new DMA implementation performs on par with the old one. (I'm starting to check). if so B. We need to thinks whether it's acceptable to kill support for video capture. In short: if (A && B) we drop old DMA else we take my patch #7