From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754136AbbIHIlI (ORCPT ); Tue, 8 Sep 2015 04:41:08 -0400 Received: from lists.s-osg.org ([54.187.51.154]:34811 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752866AbbIHIlF (ORCPT ); Tue, 8 Sep 2015 04:41:05 -0400 Subject: Re: [PATCH] ARM: exynos_defconfig: Enable USB Video Class support To: Krzysztof Kozlowski , linux-kernel@vger.kernel.org References: <1441662323-15468-1-git-send-email-javier@osg.samsung.com> <55EE9820.2010202@samsung.com> From: Javier Martinez Canillas X-Enigmail-Draft-Status: N1110 Cc: Kukjin Kim , Thierry Reding , Anand Moon , Russell King , linux-samsung-soc@vger.kernel.org, Lukasz Majewski , linux-arm-kernel@lists.infradead.org, Bartlomiej Zolnierkiewicz Message-ID: <55EE9F1A.9030703@osg.samsung.com> Date: Tue, 8 Sep 2015 10:40:58 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 MIME-Version: 1.0 In-Reply-To: <55EE9820.2010202@samsung.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [adding Bartlomiej to cc] Hello Krzysztof, On 09/08/2015 10:11 AM, Krzysztof Kozlowski wrote: > On 08.09.2015 06:45, Javier Martinez Canillas wrote: >> The Exynos5420 Peach Pit and Exynos5800 Peach Pi boards have a built-in >> Silicon Motion USB UVC WebCam. Enable support for the USB Video Class >> driver and its needed media Kconfig symbols so the camera is supported. >> >> Signed-off-by: Javier Martinez Canillas >> >> --- >> >> arch/arm/configs/exynos_defconfig | 4 ++++ >> 1 file changed, 4 insertions(+) > > The patch itself looks good but now I wonder whether we are not putting > to much stuff built-in. The exynos_defconfig does not replace the > distribution distro. For a fully working board the distro should prepare > it's own config. > Agreed that exynos_defconfig is not meant to replace a distro config. > I understand that in this case the USB webcams are parts of device (like > on all laptops)... a little bit similar as camera sensors on mobile > phones. Yet on mobile phone usually the camera itself is part of SoC, > only the sensor is external. > > Actually what we need is a kind of policy for exynos_defconfig - what > should be inside as built-in and what as module? > I had the same conversation with Bartlomiej before in [0] when I tried to enable the SBS battery driver as module. I save you a click and quote him: "the current most popular use case for exynos_defconfig (not multi_v7_defconfig) seems to be to build kernel image alone and use it without any modules" Which seems to be true, so my understanding is that exynos_defconfig is a minimal defconfig for Exynos platforms and for easy of test/use, everything should be built-in while multi_v7_defconfig would be more similar to a conf used by distros where most things would be built as a module when possible. Other SoC specific deconfig do it differently, OMAP for example does the opposite and tries to build as much stuff as possible as a module. > Best regards, > Krzysztof > > [0]: http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/278757.html Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America