From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755147AbbIWPsN (ORCPT ); Wed, 23 Sep 2015 11:48:13 -0400 Received: from mx2.suse.de ([195.135.220.15]:35315 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752507AbbIWPsL (ORCPT ); Wed, 23 Sep 2015 11:48:11 -0400 Date: Wed, 23 Sep 2015 17:48:09 +0200 From: "Luis R. Rodriguez" To: Randy Dunlap Cc: "Luis R. Rodriguez" , mmarek@suse.com, josh@joshtriplett.org, jbottomley@odin.com, geert@linux-m68k.org, pebolle@tiscali.nl, herbert@gondor.apana.org.au, tiwai@suse.de, yann.morin.1998@free.fr, corbet@lwn.net, linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, roberto@dicosmo.org, zack@upsilon.cc Subject: Re: [PATCH] kbuild: document recursive dependency limitation / resolution Message-ID: <20150923154809.GC18173@wotan.suse.de> References: <1438200556-13842-1-git-send-email-mcgrof@do-not-panic.com> <55B938EA.2080402@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55B938EA.2080402@infradead.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 29, 2015 at 01:34:50PM -0700, Randy Dunlap wrote: > On 07/29/15 13:09, Luis R. Rodriguez wrote: > > + > > +Kconfig recursive dependency limitations > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > + > > +If you've hit the Kconfig error: "recursive dependency detected" you've run > > +into a recursive dependency issue with Kconfig. Kconfig does not do recursive > > +dependency resolution, this has a few implications for Kconfig file writers. In > > maybe s/,/;/ Fixed. > > +practice it means that for instance if a driver A selects a few kconfig symbols > > +another driver B which selects any of these symbols cannot negate any of the > > +symbols the driver A selected. Because of this current limitation developers > > +who run into this type of recursive dependency issue have two diverging > > +options: > > + > > + a) Either swap all "select FOO" to "depends on FOO" or, > > + b) Change the offending "depends on FOO" to "select FOO" > > + > > +Kconfig's limitations can be addressed by implementing a SAT solver for it, > > +but until then, Kconfig is limitted to require developers to use one of > > limited > I've re-written this section, thanks for the review. Luis