Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763518AbXESXtJ (ORCPT ); Sat, 19 May 2007 19:49:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756853AbXESXs5 (ORCPT ); Sat, 19 May 2007 19:48:57 -0400 Received: from emailhub.stusta.mhn.de ([141.84.69.5]:38940 "EHLO mailhub.stusta.mhn.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752346AbXESXs4 (ORCPT ); Sat, 19 May 2007 19:48:56 -0400 Date: Sun, 20 May 2007 01:48:44 +0200 From: Adrian Bunk To: Satyam Sharma Cc: Andrew Morton , Sam Ravnborg , LKML , Roman Zippel , Kumar Gala , Simon Horman Subject: Re: RFC: kconfig select warnings bogus? Message-ID: <20070519234844.GN6291@stusta.de> References: <20070519151523.GA26724@uranus.ravnborg.org> <20070519110944.2a52061e.akpm@linux-foundation.org> <20070519230940.GJ6291@stusta.de> <20070519232542.GL6291@stusta.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1738 Lines: 43 On Sun, May 20, 2007 at 05:06:33AM +0530, Satyam Sharma wrote: > On 5/20/07, Adrian Bunk wrote: >>... >> Consider ATARI_KBD_CORE was used by 20 drivers. >> >> Using select for such not user visible helper variables is a really nice >> thing, and much more readable (and therefore much less likely to contain >> bugs) than dependencies with tons of "||"'s. > > Well, the "default .. if .." kind of idiom is fairly common (I could say > almost standard), in arch/.../config's. It's been used for some time, > and for several symbols over there. But you're right that if 20 drivers > used ATARI_KBD_CORE, we'd get tons of ugly "||"'s there, so > perhaps we do need some kind of fix for this. And the fix is to use select. Compare the handling of options like IRQ_CPU in arch/mips/Kconfig in current kernels with the handling in kernel 2.6.0 . Or as an exercise, change drivers/net/Kconfig to no longer use "select MII". When you are finished, ensure that you are handling it properly although the option is user visible... There are cases where "default .. if .." is the right idiom, but there are also cases where "select" is the right idiom. And for helper code like ATARI_KBD_CORE, "select" is the right idiom. cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed - 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/