From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from einhorn.in-berlin.de ([192.109.42.8]) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1PsbIu-0001rQ-EX for openembedded-devel@lists.openembedded.org; Thu, 24 Feb 2011 14:32:25 +0100 X-Envelope-From: sledz@dresearch.de Received: from mobil-400-586.intern.dresearch.de (p57A205C7.dip0.t-ipconnect.de [87.162.5.199]) (authenticated bits=0) by einhorn.in-berlin.de (8.13.6/8.13.6/Debian-1) with ESMTP id p1ODUw4r001574 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Thu, 24 Feb 2011 14:30:58 +0100 Received: from mobil-400-586.intern.dresearch.de (localhost [IPv6:::1]) by mobil-400-586.intern.dresearch.de (Postfix) with ESMTP id 243B72A23F; Thu, 24 Feb 2011 14:30:59 +0100 (CET) Message-ID: <4D665D92.7000100@dresearch.de> Date: Thu, 24 Feb 2011 14:30:58 +0100 From: Steffen Sledz User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.16) Gecko/20101125 SUSE/3.0.11 Lightning/1.0b1 Thunderbird/3.0.11 MIME-Version: 1.0 To: Khem Raj References: <4D5A5871.7000005@dresearch.de> <4D5A89CD.803@opendreambox.org> <4D5A92BC.1010906@dresearch.de> <4D5E422B.3040703@dresearch.de> In-Reply-To: X-Scanned-By: MIMEDefang_at_IN-Berlin_e.V. on 192.109.42.8 X-MIME-Autoconverted: from 8bit to quoted-printable by einhorn.in-berlin.de id p1ODUw4r001574 Cc: koen@openembedded.org, openembedded-devel@lists.openembedded.org Subject: Re: 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: Thu, 24 Feb 2011 13:32:25 -0000 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 02/18/2011 04:30 PM, Khem Raj wrote: > On Fri, Feb 18, 2011 at 1:55 AM, Steffen Sledz wro= te: >> Am 15.02.2011 15:50, schrieb Steffen Sledz: >>> Am 15.02.2011 15:12, schrieb Andreas Oberritter: >>>> On 02/15/2011 11:41 AM, Steffen Sledz wrote: >>>>> "Kernel headers are backwards compatible, but not forwards compatib= le. This >>>>> means that a program built against a C library using older kernel h= eaders >>>>> should run on a newer kernel (although it may not have access to ne= w >>>>> features), but a program built against newer kernel headers may not= work on an >>>>> older kernel."[2] >>>> >>>> Isn't this what the variable OLDEST_KERNEL is good for, when compili= ng >>>> glibc? >>> >>> If i'm right this goes to the --enable-kernel=3DVERSION configure opt= ion of glibc just to optimize the library. >>> >>> "the configure option --enable-kernel=3DX.Y.Z allows to strip out com= patibility for kernel versions before X.Y.Z." >>> >>> Imho it is not legitimately to follow that glibc has compatibility co= de for all kernels greater or equal X.Y.Z. >>> >>> Another question is the handling in other libc implementations. >>> >>> And finally there are a lot of programs using userland kernel headers= directly. >> >> Ping! >> >> If i interpret responses from Tom and Phil right they agree with me (o= r at least do not disagree). ;-) >> >> But i miss reactions from the distro maintainers (especially =C3=85ngs= tr=C3=B6m). >> >=20 > I think we should make sure that linux version chosen for a build is > equal or newer than linux-libc-headers for that build. Another option > is that linux-libc-headers are driven out > of selected virtual/kernel too but this may be a bit clunky since it > would mean that > every machine will have them different and we share sysroots e.g. two > armv5te may use > same sysroot I like to force the discussion/work/decision on this problem because we'r= e one of the mourners (we're forced to use 2.6.24 kernel by out hardware = vendor :( ). I also see the multi-machine problem (the shared sysroot at build time an= d the feed problem too). So what options do we (our =C3=85ngstr=C3=B6m) have? (1) Do not support kernel older than 2.6.31 (which is the current LINUX_L= IBC_HEADERS_VERSION). (2) Set LINUX_LIBC_HEADERS_VERSION to 2.6.16 (which is the current OLDEST= _KERNEL). (3) Support machine specific distro incarnations (incl. special feeds). May be some more. Option (1) would be really bad for us. I believe (2) wo= uld be bad for a lot of users because of a potential loss of functionalit= y. 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