From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC60CC00523 for ; Wed, 8 Jan 2020 10:08:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1DFB206F0 for ; Wed, 8 Jan 2020 10:08:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727579AbgAHKIk (ORCPT ); Wed, 8 Jan 2020 05:08:40 -0500 Received: from asavdk4.altibox.net ([109.247.116.15]:45684 "EHLO asavdk4.altibox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbgAHKIk (ORCPT ); Wed, 8 Jan 2020 05:08:40 -0500 Received: from ravnborg.org (unknown [158.248.194.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by asavdk4.altibox.net (Postfix) with ESMTPS id C7B5C80566; Wed, 8 Jan 2020 11:08:32 +0100 (CET) Date: Wed, 8 Jan 2020 11:08:31 +0100 From: Sam Ravnborg To: Jani Nikula Cc: Arnd Bergmann , Maarten Lankhorst , Maxime Ripard , Thierry Reding , David Airlie , Daniel Vetter , Andy Shevchenko , Randy Dunlap , Linus Walleij , Laurent Pinchart , Sean Paul , dri-devel@lists.freedesktop.org, Maxime Ripard , Emil Velikov , Boris Brezillon , linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/drm_panel: fix export of drm_panel_of_backlight, try #3 Message-ID: <20200108100831.GA23308@ravnborg.org> References: <20200107203231.920256-1-arnd@arndb.de> <87zheyqnla.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87zheyqnla.fsf@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=VcLZwmh9 c=1 sm=1 tr=0 a=UWs3HLbX/2nnQ3s7vZ42gw==:117 a=UWs3HLbX/2nnQ3s7vZ42gw==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=Vt2AcnKqAAAA:8 a=QyXUC8HyAAAA:8 a=4k1t4WDYj-Gm4IL4ZnQA:9 a=CjuIK1q_8ugA:10 a=v10HlyRyNeVhbzM4Lqgd:22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jani. On Wed, Jan 08, 2020 at 11:55:29AM +0200, Jani Nikula wrote: > On Tue, 07 Jan 2020, Arnd Bergmann wrote: > > Making this IS_REACHABLE() was still wrong, as that just determines > > whether the lower-level backlight code would be reachable from the panel > > driver. However, with CONFIG_DRM=y and CONFIG_BACKLIGHT_CLASS_DEVICE=m, > > the drm_panel_of_backlight is left out of drm_panel.o but the condition > > tells the driver that it is there, leading to multiple link errors such as > > > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-sitronix-st7701.ko] undefined! > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-sharp-ls043t1le01.ko] undefined! > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-seiko-43wvf1g.ko] undefined! > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-ronbo-rb070d30.ko] undefined! > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-rocktech-jh057n00900.ko] undefined! > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-panasonic-vvx10f034n00.ko] undefined! > > ERROR: "drm_panel_of_backlight" [drivers/gpu/drm/panel/panel-osd-osd101t2587-53ts.ko] undefined! > > > > Change the condition to check for whether the function was actually part > > of the drm module. This version of the patch survived a few hundred > > randconfig builds, so I have a good feeling this might be the last > > one for the export. > > Broken record, this will still be wrong, even if it builds and links. No > backlight support for panel despite expectations. > > See http://mid.mail-archive.com/87d0cnynst.fsf@intel.com > > All of this is just another hack until the backlight config usage is > fixed for good. Do we really want to make this the example to copy paste > wherever we hit the issue next? > > I'm not naking, but I'm not acking either. I will try to take a look at your old BACKLIGHT_CLASS_DEVICE patch this weekend. I think we need that one fixed - and then we can have this mess with "drm_panel_of_backlight" fixed in the right way. Sigh... Sam