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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 01593C2D0CD for ; Tue, 17 Dec 2019 16:06:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D45AD2465E for ; Tue, 17 Dec 2019 16:06:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728120AbfLQQG0 (ORCPT ); Tue, 17 Dec 2019 11:06:26 -0500 Received: from mga12.intel.com ([192.55.52.136]:46895 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727737AbfLQQGZ (ORCPT ); Tue, 17 Dec 2019 11:06:25 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Dec 2019 08:06:25 -0800 X-IronPort-AV: E=Sophos;i="5.69,326,1571727600"; d="scan'208";a="209748794" Received: from jnikula-mobl3.fi.intel.com (HELO localhost) ([10.237.66.161]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Dec 2019 08:06:21 -0800 From: Jani Nikula To: Andy Shevchenko Cc: Steven Price , Stephen Rothwell , intel-gfx , Randy Dunlap , Linux Kernel Mailing List , dri-devel , Linux Next Mailing List , Sam Ravnborg , Lee Jones , Daniel Thompson , Jingoo Han Subject: Re: [Intel-gfx] linux-next: Tree for Dec 16 (drm_panel & intel_panel) In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20191216162209.5b5256dd@canb.auug.org.au> <20191217054255.GA26868@ravnborg.org> <65c9dc7b-3c61-8204-07da-212632732791@infradead.org> <87d0cnynst.fsf@intel.com> Date: Tue, 17 Dec 2019 18:06:18 +0200 Message-ID: <87a77rym11.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Dec 2019, Andy Shevchenko wrote: > On Tue, Dec 17, 2019 at 5:28 PM Jani Nikula wrote: >> On Tue, 17 Dec 2019, Andy Shevchenko wrote: >> > On Tue, Dec 17, 2019 at 1:56 PM Steven Price wrote: > >> > I think the proper one is to have s/IS_ENABLED/IS_REACHABLE/. >> > It fixes issue for me. >> >> As discussed off-line, this will allow silently building and linking a >> configuration that's actually broken. (No backlight support despite >> expectations.) > > In my case I have deliberately compile backlight as a module to be > used exclusively with backlight-gpio which has nothing to do with > i915. I dunno if backlight is a MUST dependency for i915. It's not a required dependency, all combinations of i915 and backlight are fine, *except* i915=y, backlight=m. This can be achieved with: depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n BR, Jani. > > From my perspective the original commit, with all good that it > provides, should not break previously working configurations. Though > we might argue if my "working" kernel configuration had been broken in > the first place... > > Just my 2 cents, though. > >> IMO deep down the problem is that we "select" BACKLIGHT_CLASS_DEVICE all >> over the place, while we should "depends on" it. Everything else is just >> duct tape that allows configurations where built-in code calls backlight >> symbols in modules. It used to be more about an interaction with ACPI, >> now we've added DRM_PANEL to the mix. >> >> I've proposed a fix five years ago [1]. That's what it takes to fix >> these recurring failures for good. I'm not really all that interested in >> the whack-a-mole with the hacks. > > Agree with this. The root cause must be fixed once and for all. > I guess it should be a logical continuation of Sam's series. > >> [1] http://lore.kernel.org/r/1413580403-16225-1-git-send-email-jani.nikula@intel.com -- Jani Nikula, Intel Open Source Graphics Center