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=-3.8 required=3.0 tests=BAYES_00, 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 C6E5CC433B4 for ; Thu, 8 Apr 2021 10:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88C7861164 for ; Thu, 8 Apr 2021 10:21:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229714AbhDHKVW (ORCPT ); Thu, 8 Apr 2021 06:21:22 -0400 Received: from mout.kundenserver.de ([212.227.126.135]:60941 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229517AbhDHKVU (ORCPT ); Thu, 8 Apr 2021 06:21:20 -0400 Received: from mail-oi1-f169.google.com ([209.85.167.169]) by mrelayeu.kundenserver.de (mreue010 [213.165.67.97]) with ESMTPSA (Nemesis) id 1MQdpG-1lFWE61c3C-00Nj76; Thu, 08 Apr 2021 12:21:08 +0200 Received: by mail-oi1-f169.google.com with SMTP id i81so1626652oif.6; Thu, 08 Apr 2021 03:21:08 -0700 (PDT) X-Gm-Message-State: AOAM530sxuF05PDzT2jBOo8M3i32n8pLJVhYSCLGHVlZwWmzFIxsyOgu dNiMGjq03FgkfiZH3DknYTLX/D52Qg6jKSjzCnM= X-Google-Smtp-Source: ABdhPJy3jeKTxPcNwfngsbvoonksh80soCCHxiz4gKJ4G+0Fm3IstMzm5ZSVa0dFJZ+2JUBZ8yF1Sx9mjNQUOlISLnU= X-Received: by 2002:a05:6808:3d9:: with SMTP id o25mr5654228oie.4.1617877267082; Thu, 08 Apr 2021 03:21:07 -0700 (PDT) MIME-Version: 1.0 References: <20210408092011.52763-1-david@redhat.com> <20210408092011.52763-3-david@redhat.com> In-Reply-To: <20210408092011.52763-3-david@redhat.com> From: Arnd Bergmann Date: Thu, 8 Apr 2021 12:20:50 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 2/2] drivers/gpu/drm: don't select DMA_CMA or CMA from aspeed or etnaviv To: David Hildenbrand Cc: Linux Kernel Mailing List , Linux-MM , Joel Stanley , David Airlie , Daniel Vetter , Andrew Jeffery , Lucas Stach , Russell King , Christian Gmeiner , Mike Rapoport , Bartlomiej Zolnierkiewicz , Linus Walleij , Michal Simek , Masahiro Yamada , Randy Dunlap , Peter Collingbourne , linux-aspeed , dri-devel , Linux ARM , The etnaviv authors , Linux Fbdev development list Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:HYWuExe01cF59zwb7JFXEVWaI54v42eJ6tJQybH8gWFDHJxeBaC loL5xqMuS4QapORYDUtQIowlQjAz1wBbhLbigSUsH7gdX06+xx8dYPIrRUefUs4E18xhccd siCnxPqx3br3xy5SxDCES1JOPH+CPxLWbi7H3JdQEmMrnAQqJSBy6TaZVP2tCza2UaFgKEr NeCaqDyf4S3pbaerotdpA== X-UI-Out-Filterresults: notjunk:1;V03:K0:7kdEQ9WMOGE=:ludBy7ITFhUJW/Tf2bRp7J UgYmiM9UzaGV6JgHN48Udsf6ozTMG+ohcgyhy0UXCVf4NWM2j/XdhPdcMj8f1bDQg7ohvl4AA DU2tzHUhQMA4Egj5JKwEVppz1BuMc6pzHmiMBPQKbiRrj3N0TghDkav3cpsPEkoLN210A62MM cYf5h1cAtR34rtLe1h+VGJiSCwOtjAyG1rtdNLaNrob5EKC+Tu5rFq4StWb+dudTFGcuo9w6U HrWhOG+moSMVqquib4IG3nhwM2/W71Wvn3Bo3yKR8GlGt5yQP97HpOrf8j5fqqwq/5tV5WrIC 7hTK5uqPL1oZKA0EmX0wGV806hyFL4n+x0BChnhyoVlE6f8Ln5IXx54Qgy7So3BBWMMSFLbJI G90jn4Q1qmB5NwchaN8/JtyvndbhuEvjGj8l3C1KBrrReBtQvfqHAHGD4lDP12qt3p52aCeVA DeroMFGxUcAPOMV1ZUH6pfmoTfBCIc8ZoYDnro+gEu8s5iE00yuPzHqUi/SMFUB1pbZW2sw96 GvgapO+jocqevyRsM1tgmRtk8Dxym8qbzpyN+qD0UG6yrb6VxmCabJuGM5/oIZGeKk5760eiv 5h1MiIqWlVHythk+mXyRcz5aTpr4mARlkf Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Thu, Apr 8, 2021 at 11:22 AM David Hildenbrand wrote: > > Random drivers should not override a user configuration of core knobs > (e.g., CONFIG_DMA_CMA=n). Use "imply" instead, to still respect > dependencies and manual overrides. > > "This is similar to "select" as it enforces a lower limit on another > symbol except that the "implied" symbol's value may still be set to n > from a direct dependency or with a visible prompt." > > Implying DRM_CMA should be sufficient, as that depends on CMA. > > Note: If this is a real dependency, we should use "depends on DMA_CMA" > instead - but I assume the driver can work without CMA just fine -- > esp. when we wouldn't have HAVE_DMA_CONTIGUOUS right now. 'imply' is almost never the right solution, and it tends to cause more problems than it solves. In particular, it does not prevent a configuration with 'DRM_CMA=m' and 'DRMA_ASPEED_GFX=y', or any build failures from such a configuration. If you want this kind of soft dependency, you need 'depends on DRM_CMA || !DRM_CMA'. Arnd