From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755594Ab1I3Pcl (ORCPT ); Fri, 30 Sep 2011 11:32:41 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:45291 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754763Ab1I3Pck convert rfc822-to-8bit (ORCPT ); Fri, 30 Sep 2011 11:32:40 -0400 MIME-Version: 1.0 In-Reply-To: <20110930152517.GE19053@somewhere> References: <20110930134245.GB21474@localhost.pp.htv.fi> <20110930150519.GA7980@leaf> <20110930152517.GE19053@somewhere> Date: Fri, 30 Sep 2011 17:32:39 +0200 Message-ID: Subject: Re: Please revert "debug: Make CONFIG_EXPERT select CONFIG_DEBUG_KERNEL to unhide debug options" From: Frederic Weisbecker To: Josh Triplett Cc: Adrian Bunk , Linus Torvalds , linux-kernel@vger.kernel.org, Sam Ravnborg Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2011/9/30 Frederic Weisbecker : > On Fri, Sep 30, 2011 at 08:05:19AM -0700, Josh Triplett wrote: >> On Fri, Sep 30, 2011 at 04:42:45PM +0300, Adrian Bunk wrote: >> > I was just wondering why I was asked about all the debug options when I >> > tried 3.1-rc8, and that was due to commit f505c553 (debug: Make >> > CONFIG_EXPERT select CONFIG_DEBUG_KERNEL to unhide debug options), >> > the full commit is below. >> > >> > It is wrong, and the author does not seem to understand how Kconfig works. >> > >> > The commit message is: >> > >> >     Several debugging options currently default to y, such as >> >     CONFIG_DEBUG_BUGVERBOSE and CONFIG_DEBUG_RODATA.  Embedded users >> >     might want to turn those options off to save space; however, >> >     turning them off requires turning on CONFIG_DEBUG_KERNEL to >> >     unhide them.  Since CONFIG_DEBUG_KERNEL exists specifically to >> >     unhide debugging options, and CONFIG_EXPERT exists specifically >> >     to unhide options potentially needed by experts and/or embedded >> >     users, make CONFIG_EXPERT automatically imply >> >     CONFIG_DEBUG_KERNEL. >> > >> > >> > Let me point at the obvious fact that both CONFIG_DEBUG_BUGVERBOSE and >> > CONFIG_DEBUG_RODATA do depend on DEBUG_KERNEL, and are contrary to the >> > claim of the author of this patch never enabled with >> > CONFIG_DEBUG_KERNEL=n. [1] >> >> Not true: >> >> ~/src/linux-2.6$ rm .config >> ~/src/linux-2.6$ make allnoconfig >>   HOSTCC  scripts/basic/fixdep >>   HOSTCC  scripts/kconfig/conf.o >>   HOSTCC  scripts/kconfig/zconf.tab.o >>   HOSTLD  scripts/kconfig/conf >> scripts/kconfig/conf --allnoconfig Kconfig >> # >> # configuration written to .config >> # >> ~/src/linux-2.6$ grep BUGVERBOSE .config >> CONFIG_DEBUG_BUGVERBOSE=y >> ~/src/linux-2.6$ grep DEBUG_KERNEL .config >> # CONFIG_DEBUG_KERNEL is not set >> >> DEBUG_BUGVERBOSE does not depend on DEBUG_KERNEL; it just only shows up >> with DEBUG_KERNEL (and EXPERT) set.  The *description* has a conditional >> on DEBUG_KERNEL and EXPERT: >> >> config DEBUG_BUGVERBOSE >>         bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT >> >> That doesn't mean the same thing as "depends on DEBUG_KERNEL". > > Indeed. > > But for DEBUG_RODATA it is the case. That said given the issue described > with DEBUG_BUGVERSBOSE, it makes only the changelog buggy, not the patch. > > Also the patch was supposed to have a broader cleanup effect: > https://lkml.org/lkml/2011/6/6/641 > > But we applied an earlier version by accident. > > All in one I think we chose a wrong way to fix the issue. It's annoying to > have all the configs that are only visible with CONFIG_EXPERT spread all > around in random config menu. > > Anything that has "if CONFIG_EXPERT" should probably be moved under the CONFIG_EXPERT > menu so that it's visible and found right away. > But now I realize there are too many things all around that have "if EXPERT". So I guess we need to continue that way :)