Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752444AbbFXKS1 (ORCPT ); Wed, 24 Jun 2015 06:18:27 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:65275 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751749AbbFXKSS (ORCPT ); Wed, 24 Jun 2015 06:18:18 -0400 Message-ID: <558A83E8.4070707@nod.at> Date: Wed, 24 Jun 2015 12:18:16 +0200 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: "Enrico Weigelt, metux IT consult" CC: "Luis R. Rodriguez" , "backports@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Julia Lawall Subject: Re: Uses of Linux backports in the industry References: <55687D72.3070904@melag.de> <558A73D9.3060703@melag.de> <558A760B.2030600@nod.at> <558A7EA3.3040809@melag.de> In-Reply-To: <558A7EA3.3040809@melag.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2000 Lines: 49 Am 24.06.2015 um 11:55 schrieb Enrico Weigelt, metux IT consult: > Am 24.06.2015 um 11:19 schrieb Richard Weinberger: > > Hi, > >> Porting PREEMPT_RT is not that easy. >> Did you ever? > > I know. > > OTOH, is backporting drivers to ancient kernels (where internal APIs > often are _completely_ different) really easier ? Perhaps it might look > so, if it's just one individual driver - but often it doesn't keep this > way, sooner or later other things pop up. At the end of the day customers will do what is less costly. Sometimes backporting a driver is much less effort. That's why we have the excellent backports project. >> So, you rewrite all drivers and the board support from scratch? > > Sometimes, if I have to. Because - on my own experience - what SoC > vendors provide usually is pretty unusable, just a quick showcase. > > Right now, I'm working on a project w/ some imx53-based board. > What freescale provides here is practically unusable. Really ancient > (last time I checked, it was an old 2.6.x), unsable and insecure > (anybody had a closer look at their "kgsl" patch or their gst-plugin ?) > > We'll have to drop the whole idea of using the GPUs, due to lack of > support - the existing driver/libgl is known to be broken and insecure, > no support from fsl whatsoever, we're lacking resources for a full > reverse engineering, and moving to another SoC is out of question > (at least for the forseeable future). So, it ends up in having no > GPU, therefore no GL/GSL, therefore no QtQuick/QML. > > > Pavel already mentioned the correct way to go: chip vendors should > provide proper (mainline'able) patches, or at least full specs. Sure, in a perfect world. But as of now we have to deal with that. Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/