From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from proxy.dresearch.de ([87.193.137.100] helo=mail.dresearch.de) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1PpINE-0004hi-Ho for openembedded-devel@lists.openembedded.org; Tue, 15 Feb 2011 11:43:12 +0100 Received: from exchange.intern.dresearch.de (owa.xfer-intern.dresearch.de [192.168.32.16]) by mail.dresearch.de (Postfix) with ESMTP id 30FC1491283 for ; Tue, 15 Feb 2011 11:41:58 +0100 (CET) Received: from [127.0.0.1] ([10.32.10.2]) by exchange.intern.dresearch.de with Microsoft SMTPSVC(6.0.3790.4675); Tue, 15 Feb 2011 11:41:58 +0100 Message-ID: <4D5A5871.7000005@dresearch.de> Date: Tue, 15 Feb 2011 11:41:53 +0100 From: Steffen Sledz User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.2.13) Gecko/20101207 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: openembedded-devel X-OriginalArrivalTime: 15 Feb 2011 10:41:58.0186 (UTC) FILETIME=[F86C40A0:01CBCCFC] Subject: linux-libc-headers version (reloaded) 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: Tue, 15 Feb 2011 10:43:12 -0000 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable While doing some maintenance for our hipox machine i hit a problem which = was discussed controversially a few months before on this ML[1] but was n= ot solved completely in my opinion. The basic question was if it is valid to use PREFERRED_VERSION_linux-libc= -headers higher than the kernel version (like e.g angstrom-2008.1 does). After some research on that topic i really believe this is not allowed. M= y strongest argument is the kernel docu itself: "Kernel headers are backwards compatible, but not forwards compatible. T= his means that a program built against a C library using older kernel headers should run on a newer kernel (although it may not have access to new features), but a program built against newer kernel headers may not work = on an older kernel."[2] Also i did not found a linux distribution providing kernel headers newer = than the kernel (whilst there are some with kernel headers older than the= used kernel, e.g. openSUSE 11.3 with latest updates). So i think the way the =C3=85ngstr=C3=B6m distribution handles this is wr= ong. If PREFERRED_VERSION_linux-libc-headers is set to 2.6.31 no kernel o= lder than 2.6.31 should be allowed to guarantee the full functionality of= all programs! [1] [2] Documentation/make/headers_install.txt Steffen --=20 DResearch Fahrzeugelektronik GmbH Otto-Schmirgal-Str. 3, 10319 Berlin, Germany Tel: +49 30 515932-237 mailto:sledz@DResearch.de Fax: +49 30 515932-299 Gesch=C3=A4ftsf=C3=BChrer: Dr. Michael Weber, Werner M=C3=B6gle; Amtsgericht Berlin Charlottenburg; HRB 130120 B; Ust.-IDNr. DE273952058