Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751463AbbFXJz6 (ORCPT ); Wed, 24 Jun 2015 05:55:58 -0400 Received: from mail.melag.de ([217.6.74.107]:54903 "EHLO mail.melag.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408AbbFXJzu convert rfc822-to-8bit (ORCPT ); Wed, 24 Jun 2015 05:55:50 -0400 Message-ID: <558A7EA3.3040809@melag.de> Date: Wed, 24 Jun 2015 11:55:47 +0200 From: "Enrico Weigelt, metux IT consult" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Richard Weinberger 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> In-Reply-To: <558A760B.2030600@nod.at> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8BIT X-Originating-IP: [192.168.57.169] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2870 Lines: 51 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. > 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. And I'll add: those who dont, should simply be boycotted. cu -- Enrico Weigelt, metux IT consult +49-151-27565287 MELAG Medizintechnik oHG Sitz Berlin Registergericht AG Charlottenburg HRA 21333 B Wichtiger Hinweis: Diese Nachricht kann vertrauliche oder nur für einen begrenzten Personenkreis bestimmte Informationen enthalten. Sie ist ausschließlich für denjenigen bestimmt, an den sie gerichtet worden ist. Wenn Sie nicht der Adressat dieser E-Mail sind, dürfen Sie diese nicht kopieren, weiterleiten, weitergeben oder sie ganz oder teilweise in irgendeiner Weise nutzen. Sollten Sie diese E-Mail irrtümlich erhalten haben, so benachrichtigen Sie bitte den Absender, indem Sie auf diese Nachricht antworten. Bitte löschen Sie in diesem Fall diese Nachricht und alle Anhänge, ohne eine Kopie zu behalten. Important Notice: This message may contain confidential or privileged information. It is intended only for the person it was addressed to. If you are not the intended recipient of this email you may not copy, forward, disclose or otherwise use it or any part of it in any form whatsoever. If you received this email in error please notify the sender by replying and delete this message and any attachments without retaining a copy. -- 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/