Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3EEBC433EF for ; Tue, 7 Dec 2021 13:02:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236802AbhLGNFp (ORCPT ); Tue, 7 Dec 2021 08:05:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236717AbhLGNFo (ORCPT ); Tue, 7 Dec 2021 08:05:44 -0500 Received: from lb1-smtp-cloud9.xs4all.net (lb1-smtp-cloud9.xs4all.net [IPv6:2001:888:0:108::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C95BC061574; Tue, 7 Dec 2021 05:02:13 -0800 (PST) Received: from cust-b5b5937f ([IPv6:fc0c:c16d:66b8:757f:c639:739b:9d66:799d]) by smtp-cloud9.xs4all.net with ESMTPA id ua6hm8RaalcdAua6kmmAdR; Tue, 07 Dec 2021 14:02:12 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=xs4all.nl; s=s2; t=1638882132; bh=Yt4VY8ambnxcmyU8WM3Nofvl83aZYAnuuv5nqZx0eTg=; h=Subject:To:From:Message-ID:Date:MIME-Version:Content-Type:From: Subject; b=Hxrg/Djz4MChK45dg55U7AIRpg+M6WoqyYB9JQkexihGt9MJX5xNxpLU6XI9hrlre 6p4lz5Ffs3Zqm1MSNP3DcHBUCbo+GwyPBD1k65mn1RiED6OrPnlroypvCO0ZAmAp2d tYx+T9buzKtoiNLHYMKVi9pjbsOvqn1eTyR+gQxJadh/aFrZyH/U0KXmGckseYhSGL 4+GRFAPsuOFBuGN64SsSxN183HEaGhe2zS/FdlwCrZKi8ss+7auTs7UyWzZ3EiKamd 6zea85qGwFS1iI79nD5Es3Ufg2FJ5MPuohZoJLUv+3Bs3RJec6zaYVTnnCDcUCcGL2 tf8d//f3cIbcg== Subject: Re: [PATCH v7 2/7] mtk-mdp: add driver to probe mdp components To: Ezequiel Garcia Cc: houlong wei , Eizan Miyamoto , Linux Kernel Mailing List , "chunkuang.hu@kernel.org" , =?UTF-8?B?WW9uZyBXdSAo5ZC05YuHKQ==?= , "wenst@chromium.org" , =?UTF-8?B?Q0sgSHUgKOiDoeS/ig==?= =?UTF-8?B?5YWJKQ==?= , Enric Balletbo i Serra , =?UTF-8?B?WW9uZ3FpYW5nIE5pdSAo54mb5rC45by6KQ==?= , =?UTF-8?B?QW5kcmV3LUNUIENoZW4gKOmZs+aZuui/qik=?= , Matthias Brugger , Mauro Carvalho Chehab , =?UTF-8?B?TWluZ2hzaXUgVHNhaSAo6JSh5piO5L+uKQ==?= , linux-arm-kernel , linux-media , "moderated list:ARM/Mediatek SoC support" References: <20210825063323.3607738-1-eizan@chromium.org> <20210825163247.v7.2.Ie6d1e6e39cf9b5d6b2108ae1096af34c3d55880b@changeid> From: Hans Verkuil Message-ID: Date: Tue, 7 Dec 2021 14:02:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4xfOGBdAXbSiNV8TnHDwlxXnJeIohGqJ8BZ7Z0kW8d/GDeEafF13KJ5xYm8S/80Uug+X9+/GmjAgWAP0hs80ijIRrUiJMpD2FlTjQ/is0WHay0dEhiRQhV jy4P1sQB0mL9K2H3mzedhtk9WPqP4FiTt+o4V9pJzhZXhZMJ8SBGXcSdT3v0vgnAp3pEx99F4AHra4ieCAE8/EfbAg9esYDau5aRIF2uqCsUCgDpbUJyPP8q GXycsa+Gzm8OMY8dFX65udksjhLzax6RQtvBdqo/DOv/3xYuwn1Dxv9pYr5gh5mWWlMNF54un+0mtp/YGwr1vwqnJJIlejJ78FP2vjqgU5bfQU7FcKichO85 kL9zgggxsaO6CKl0BakaUZEm+Absn8oReNywxro4uK57ucqwmAzdfTfxtTXdxYgM0tbXk0/ud3c3AcNGrfETOxmnGihfL4x0B6fnVJxf4uLAessRm/ZDnSwm Cdr0D+5hQUsyktfCW6kTCMHxEfovuOIik2t+u73DLaNYgUFUMvHUYpz9V2v1vpOll8RHZC2dgpbU6LHbTh1aCjnfNq5kZ7X1ctWoX37cpuSxcpiGGHUiF1cc rYwIvVS4a7ADqcyb61ja2Y+9+iUBy9CRY475nt7i/+GafvrBD3pRCe+G+7f86J+GmF7xxFSOWgoUNRPjJjwxZsaqRrqHc2XGIIMNi5XY59H+InqouWLJLspi upg1UGp8rIkzMC5KlgBVuUOivlhnfksjurOQyJhkyxIX0z1UMT9FnHhJnG/AyttXGqsZVfC4v4P2pFzRjr6viWkaw4fzX4LHpsWUzjx9K+3cFf2B0NDj1uvs U6513aGHxKAfQh1VMVc9hlpkb30TD+kJ3Aej5iqsEk/tgHHlGSbgSuStK2Xb9kB702+4jUIRV2r+sWWPn1M= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/7/21 1:46 PM, Ezequiel Garcia wrote: > Hi everyone, > > On Tue, 7 Dec 2021 at 09:37, Hans Verkuil wrote: >> >> On 9/5/21 6:23 PM, houlong wei wrote: >>> Hi Ezequiel, >>> >>> Thank you for your attention to this series of patches. I answer partial of your questions below. >>> Regards, >>> Houlong >>> >>> On Sat, 2021-09-04 at 20:34 +0800, Ezequiel Garcia wrote: >>>> Hi Eizan, >>>> >>>> Sorry for seeing this series so late. >>>> >>>> On Wed, 25 Aug 2021 at 03:35, Eizan Miyamoto >>>> wrote: >>>>> >>>>> Broadly, this patch (1) adds a driver for various MTK MDP >>>>> components to >>>>> go alongside the main MTK MDP driver, and (2) hooks them all >>>>> together >>>>> using the component framework. >>>>> >>>>> (1) Up until now, the MTK MDP driver controls 8 devices in the >>>>> device >>>>> tree on its own. When running tests for the hardware video decoder, >>>>> we >>>>> found that the iommus and LARBs were not being properly configured. >>>> >>>> Why were not being properly configured? What was the problem? >>>> Why not fixing that instead? >>>> >>>> Does this mean the driver is currently broken and unusable? >>> >>> This series of patches are supplements to another series, please refer >>> to >>> https://patchwork.kernel.org/project/linux-mediatek/list/?series=515129c >>> , which add device link between the mtk-iommu consumer and the mtk-larb >>> devices. Without that series of patches, the mtk-mdp driver can work >>> well so far. >>> But with that series, it seems the device link only can be established >>> for the device which is registered as a platform driver. That's why >>> Eizan adds this series of patches to make all mdp components to be >>> registered as platform drivers. >> >> Hold on, so this means that if that iommu device-link series is merged, >> then the mtk-mdp driver breaks? I posted a PR for that iommu series, but >> I've just withdrawn that PR until this issue is clarified. >> >> Is it only mtk-mdp that is affected by this iommu device-link series, or >> others as well? >> > > Like I said before, I think it's a mistake to introduce the component > framework in V4L2. This whole idea looks like a hack to me. > > If we merge this, then we validate using the component framework > as a way to avoid fixing things properly. I agree with Ezequiel. Hans