From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-bw0-f47.google.com ([209.85.214.47]) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1QVgsX-0007q3-QO for openembedded-devel@lists.openembedded.org; Sun, 12 Jun 2011 11:22:45 +0200 Received: by bwz5 with SMTP id 5so3686283bwz.6 for ; Sun, 12 Jun 2011 02:19:23 -0700 (PDT) Received: by 10.204.80.74 with SMTP id s10mr3383488bkk.4.1307870362763; Sun, 12 Jun 2011 02:19:22 -0700 (PDT) Received: from mobil-400-586.intern.dresearch.de (ip-109-40-245-22.web.vodafone.de [109.40.245.22]) by mx.google.com with ESMTPS id af13sm4237325bkc.7.2011.06.12.02.19.20 (version=SSLv3 cipher=OTHER); Sun, 12 Jun 2011 02:19:21 -0700 (PDT) Message-ID: <4DF48491.6070901@dresearch-fe.de> Date: Sun, 12 Jun 2011 11:19:13 +0200 From: Steffen Sledz User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110414 SUSE/3.1.10 Thunderbird/3.1.10 MIME-Version: 1.0 To: openembedded-devel@lists.openembedded.org References: <4DF0C472.4030608@dresearch-fe.de> <4DF14C7E.7000701@gmail.com> In-Reply-To: <4DF14C7E.7000701@gmail.com> Subject: Re: Distros supporting older kernels? X-BeenThere: openembedded-devel@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: openembedded-devel@lists.openembedded.org List-Id: Using the OpenEmbedded metadata to build Distributions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 Jun 2011 09:22:45 -0000 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10.06.2011 00:43, Khem Raj wrote: > On 06/09/2011 06:02 AM, Steffen Sledz wrote: >> Hi Distro Maintainers, >> >> as you could read in earlier messages of mine, we're forced to use an >> older kernel version (2.6.24) for our hardware. This brings a lot of >> problems as you can imagine (e.g. we're also bound to udev-141). >> >> Until now we've used angstrom-2008.1 with some own patches according to >> the linux-libc-headers and udev versions for our hardware which were >> reasonably not accepted by the Angstrom maintainers (see discussions [1] >> or [2]). >> >> In there current situation (angstrom-2008.1 is deprecated, the new layer >> concept will come up) we're looking for a new, better, less hacky solution. >> >> My first question therefor is if there are any distros explicitely >> supporting older kernels (pre 2.6.27) yet? Or are willing to work on it? >> > > I guess a machine layer on top of oe-core could be something you can work out and add/override needed recipes in this layer. I think it's not that easy. For kernels prior to 2.6.27 you can't use a lot of core components (e.g. udev with versions higher than 141 or eggdbus) which *a lot of other components* depend on. The underlying problem are some kernel API functions like inotify_init1 or epoll_create1. Some distros (e.g. Angstrom) use linux-libc-headers 2.6.31 which is higher then 2.6.27 (what in my opinion conflicts with [1]). So there's no chance to detect the mentioned kernel functions correctly at compile time. :( As a consequence you have to check this in *all* programs at runtime. This is a good wish but hard to realize. E.g. the udev maintainers itself rejected a related patch[2] and say that they are not willing to support older kernel versions. So in my opinion there are two possible ways: 1. Use only the old supported versions of the components (udev-141 and glib-dbus instead of eggdbus) with all the consequences for other programs. 2. Determine *all* critical kernel functions, look for *all* the places where these are used, and patch them. Both are a lot more than some override recipes. So i think this needs an own distro with all the maintenance and testing. Regards, Steffen [1] "but a program built against newer kernel headers may not work on an older kernel" [2] -- DResearch Fahrzeugelektronik GmbH Otto-Schmirgal-Str. 3, 10319 Berlin, Germany Tel: +49 30 515932-237 mailto:sledz@dresearch-fe.de Fax: +49 30 515932-299 Geschäftsführer: Dr. Michael Weber, Werner Mögle; Amtsgericht Berlin Charlottenburg; HRB 130120 B; Ust.-IDNr. DE273952058