Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759214Ab0GPUKQ (ORCPT ); Fri, 16 Jul 2010 16:10:16 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:40901 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759158Ab0GPUKO (ORCPT ); Fri, 16 Jul 2010 16:10:14 -0400 Subject: Re: [RFC PATCH] Kconfig: Enable Kconfig fragments to be used for defconfig From: Catalin Marinas To: Linus Torvalds Cc: Nicolas Pitre , Stephen Rothwell , Daniel Walker , Russell King - ARM Linux , linux-kbuild@vger.kernel.org, Tony Lindgren , Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= , lkml , Grant Likely , Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org In-Reply-To: References: <20100713230352.6781.18644.stgit@angua> <1279296221.17878.66.camel@e102109-lin.cambridge.arm.com> <20100716183028.GB26854@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="UTF-8" Organization: ARM Limited Date: Fri, 16 Jul 2010 21:09:36 +0100 Message-ID: <1279310976.18579.8.camel@e102109-lin.cambridge.arm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 16 Jul 2010 20:09:37.0623 (UTC) FILETIME=[D1076670:01CB2522] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1249 Lines: 36 On Fri, 2010-07-16 at 19:46 +0100, Linus Torvalds wrote: > On Fri, Jul 16, 2010 at 11:40 AM, Nicolas Pitre wrote: > > > > DOH. > > Well, it's possible that the correct approach is a mixture. > > Automatically do the trivial cases (recursive selects, dependencies > that are simple or of the form "x && y" etc), and warn about the cases > that aren't trivial (where "not trivial" may not necessarily be about > fundamentally ambiguous ones, but just "complex enough that I won't > even try"). There is still a risk with this approach when the Kconfig isn't entirely correct. For example, on ARM we have (I pushed a patch already): config CPU_32v6K depends on CPU_V6 config CPU_V7 select CPU_32v6K In this simple approach, we end up selecting CPU_V6 when we only need CPU_V7. There other places like this in the kernel. Of course, kbuild could still warn but if people rely on this feature to select options automatically I suspect they would ignore the warnings. -- Catalin -- 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/