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 78D37C43461 for ; Thu, 8 Apr 2021 20:29:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CACE261159 for ; Thu, 8 Apr 2021 20:29:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CACE261159 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 124366B006C; Thu, 8 Apr 2021 16:29:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0D4E06B006E; Thu, 8 Apr 2021 16:29:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EB6DF6B0071; Thu, 8 Apr 2021 16:29:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0240.hostedemail.com [216.40.44.240]) by kanga.kvack.org (Postfix) with ESMTP id C97076B006C for ; Thu, 8 Apr 2021 16:29:36 -0400 (EDT) Received: from smtpin37.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 80329181CC1AF for ; Thu, 8 Apr 2021 20:29:36 +0000 (UTC) X-FDA: 78010340352.37.136D7D2 Received: from mout.kundenserver.de (mout.kundenserver.de [217.72.192.75]) by imf13.hostedemail.com (Postfix) with ESMTP id 5713CE000108 for ; Thu, 8 Apr 2021 20:29:33 +0000 (UTC) Received: from mail-ot1-f43.google.com ([209.85.210.43]) by mrelayeu.kundenserver.de (mreue109 [213.165.67.113]) with ESMTPSA (Nemesis) id 1MSbp1-1l1dDw3BDl-00Su1k for ; Thu, 08 Apr 2021 22:29:34 +0200 Received: by mail-ot1-f43.google.com with SMTP id y19-20020a0568301d93b02901b9f88a238eso3568118oti.11 for ; Thu, 08 Apr 2021 13:29:33 -0700 (PDT) X-Gm-Message-State: AOAM532SaXebQxz64zJipwbX2EFxxU/KqBnHiubUXeD/bXVm32925ME4 SSEpHsSMUKP8BR5Sfu2FWXreMGRrze7ExsRro/o= X-Google-Smtp-Source: ABdhPJyfPECLeLOF/Bs3NvQ2GDzKFAUyLZwtkCfbxO3pPqunDWbqv1JOjJ/RM4Y98JdJ7lIhjCGjr/ZYV8r3IjuTvvw= X-Received: by 2002:a05:6830:148c:: with SMTP id s12mr9613770otq.251.1617913771943; Thu, 08 Apr 2021 13:29:31 -0700 (PDT) MIME-Version: 1.0 References: <20210408092011.52763-1-david@redhat.com> <20210408092011.52763-3-david@redhat.com> <7496ac87-9676-1b4e-3444-c2a662ec376b@redhat.com> <3a2d64a7-8425-8daf-17ee-95b9f0c635f9@redhat.com> <2ef3b65c-c0ef-7bbe-0e05-39ee8f2bae48@redhat.com> In-Reply-To: <2ef3b65c-c0ef-7bbe-0e05-39ee8f2bae48@redhat.com> From: Arnd Bergmann Date: Thu, 8 Apr 2021 22:29:15 +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: Linus Walleij , Linux Kernel Mailing List , Linux-MM , Joel Stanley , David Airlie , Daniel Vetter , Andrew Jeffery , Lucas Stach , Russell King , Christian Gmeiner , Mike Rapoport , Bartlomiej Zolnierkiewicz , 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:D8gZG6tuslEG3YNd5g8nCxszqfczYDJBLN3I7QanmCU2kEQSxnv 2lbrcWNEK+PmGMCdoMW8iNROLrO6VaFPtdQ/wX5Wid/N/Jh1VeAtv4Ac/tCq9LUTfg5WAeK ns17q3fAbCInVtDmkg6dAOxRbdDpUyK1Kucp62WDIir3F/qoJK2wraSewUakKRoFiK2HUsO l/v+N0tZMvvjQCyZbT8tg== X-UI-Out-Filterresults: notjunk:1;V03:K0:/6rv9GKiBJo=:SH420r8hTb10HT60wHm7Ql +e6+lXfUa2+/4yVhlTwCnJ6cWVPdCarUo7UuArnpGRxwWdTSNcuFTmVLu6dqbWD+it3cHnsGl 20oMQGrNH/slxYkw9XRoxG/z0Cc2WWMqogT2ni3hM23kJ80UWtdWhNLR1tO0Cze1HWRmkEStw qcqzvtp8CFdPg3mKsYsE21Y6Bk6umm99RGpWVGuFjys4ET4ZpBjf9jvPXMv+t+BltuH6BwisH BlC1yRW74ZHmH+9stLIHeG/r6QJKvOqEDfP8Mch1hkh/by9gVqWrZ+ODoY4n7F8c8SlbYzfXE sS9cv+3yQfB426qaExvm3UpX1kTFdijZY1bCSraXFxqSPwMeEJgFV3D9l3fj6yrFDqeptjAM2 zwPUpcXVYdPcoIFYwU0TruJ4QAVWhiXB4Aq1vogDBJ3dNYSmTaJABAC0prW90B0x3vYlUIpR7 RLaDLlM1hL12WjkhmdSUmGtYO7c7WSbbkERkKIItEwsp7Nz7jqZwxq5fW4/vri3w9oG/4tsNE jkXey6xNelervHsfFaeUdBE1jADnWurv+vPp8uwF8oHKyodWu2q/9x+mvYuwYWiO50Nd4g6hK E/TvM2xm8RXApy4mhll/qGGVmUUbtURbrl X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 5713CE000108 X-Stat-Signature: ch5mygdnbqdmk4syfhofgex8nz4mfrzx Received-SPF: none (arndb.de>: No applicable sender policy available) receiver=imf13; identity=mailfrom; envelope-from=""; helo=mout.kundenserver.de; client-ip=217.72.192.75 X-HE-DKIM-Result: none/none X-HE-Tag: 1617913773-653222 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Apr 8, 2021 at 6:45 PM David Hildenbrand wrote: > On 08.04.21 14:49, Linus Walleij wrote: > > On Thu, Apr 8, 2021 at 2:01 PM David Hildenbrand wrote: > > > >>> This is something you could do using a hidden helper symbol like > >>> > >>> config DRMA_ASPEED_GFX > >>> bool "Aspeed display driver" > >>> select DRM_WANT_CMA > >>> > >>> config DRM_WANT_CMA > >>> bool > >>> help > >>> Select this from any driver that benefits from CMA being enabled > >>> > >>> config DMA_CMA > >>> bool "Use CMA helpers for DRM" > >>> default DRM_WANT_CMA > >>> > >>> Arnd > >>> > >> > >> That's precisely what I had first, with an additional "WANT_CMA" -- but > >> looking at the number of such existing options (I was able to spot 1 !) > > > > If you do this it probably makes sense to fix a few other drivers > > Kconfig in the process. It's not just a problem with your driver. > > "my" drivers: > > > > :) I actually wanted to convert them to "depends on DMA_CMA" but ran > into recursive dependencies ... > > > drivers/gpu/drm/mcde/Kconfig > > drivers/gpu/drm/pl111/Kconfig > > drivers/gpu/drm/tve200/Kconfig Right, this is the main problem caused by using 'select' to force-enable symbols that other drivers depend on. Usually, the answer is to be consistent about the use of 'select' and 'depends on', using the former only to enable symbols that are hidden, while using 'depends on' for anything that is an actual build time dependency. > I was assuming these are "real" dependencies. Will it also work without > DMA_CMA? I think in this case, it is fairly likely to work without DMA_CMA when the probe function gets called during a fresh boot, but fairly likely to fail if it gets called after the system has run for long enough to fragment the free memory. The point of DMA_CMA is to make it work reliably. Arnd