From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755298AbYEDIsv (ORCPT ); Sun, 4 May 2008 04:48:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753235AbYEDIso (ORCPT ); Sun, 4 May 2008 04:48:44 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:39602 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752954AbYEDIsn (ORCPT ); Sun, 4 May 2008 04:48:43 -0400 Date: Sun, 4 May 2008 10:48:21 +0200 From: Ingo Molnar To: Vegard Nossum Cc: Roman Zippel , Adrian Bunk , Sam Ravnborg , linux-kernel@vger.kernel.org Subject: Re: [PATCH] kconfig: warn about complex selects Message-ID: <20080504084821.GC21859@elte.hu> References: <20080504054044.GA32030@damson> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080504054044.GA32030@damson> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Vegard Nossum wrote: > Hi, > > Given recent discussion about kconfig and the "select" feature, I have made > the following quick & dirty patch to detect what I call "complex selects". > > For v2.6.25, I get these warnings: > sound/pci/Kconfig:512:error: found complex select: SND_FM801_TEA575X -> VIDEO_V4L1 > drivers/ide/Kconfig:890:error: found complex select: ETRAX_IDE -> BLK_DEV_IDEDMA > drivers/acpi/Kconfig:185:error: found complex select: ACPI_HOTPLUG_CPU -> ACPI_CONTAINER > > While for v2.6.26-rc1, I get these: > sound/pci/Kconfig:528:error: found complex select: SND_FM801_TEA575X -> VIDEO_V4L1 > drivers/media/video/em28xx/Kconfig:2:error: found complex select: VIDEO_EM28XX -> MEDIA_TUNER > drivers/media/video/bt8xx/Kconfig:2:error: found complex select: VIDEO_BT848 -> MEDIA_TUNER > drivers/media/video/saa7134/Kconfig:2:error: found complex select: VIDEO_SAA7134 -> MEDIA_TUNER > drivers/media/video/cx88/Kconfig:2:error: found complex select: VIDEO_CX88 -> MEDIA_TUNER > drivers/media/video/cx23885/Kconfig:2:error: found complex select: VIDEO_CX23885 -> MEDIA_TUNER > drivers/media/video/ivtv/Kconfig:2:error: found complex select: VIDEO_IVTV -> MEDIA_TUNER > drivers/media/video/cx18/Kconfig:2:error: found complex select: VIDEO_CX18 -> MEDIA_TUNER > drivers/media/video/pvrusb2/Kconfig:2:error: found complex select: VIDEO_PVRUSB2 -> MEDIA_TUNER > drivers/media/video/Kconfig:690:error: found complex select: VIDEO_MXB -> MEDIA_TUNER > drivers/media/video/usbvision/Kconfig:2:error: found complex select: VIDEO_USBVISION -> MEDIA_TUNER > drivers/acpi/Kconfig:188:error: found complex select: ACPI_HOTPLUG_CPU -> ACPI_CONTAINER > > (In other words, the number of these has increased significantly since > the last release, and these will probably be hit as compile errors at > one point or another.) wow - these are exactly the problems that have been implicated statistically via all the build failures. and this concurs with my observation about build failures in this cycle - 2.6.26 showed a sharp rise in Kconfig space build problems. (and i've been doing random build tests for a long time) so your patch is pure gold. A thirty-line quick hack like this if implemented years ago could have avoided dozens and dozens of build failures and anguish to users, and we'd have lots less trivial patches littering the commit logs (and wasting maintainer and review bandwidth) as well. (because maintainers could act on these messages right when they introduce the select complexity, avoiding such bugs right at their source.) Ingo