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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 E7B6FC7C862 for ; Mon, 27 Apr 2020 11:41:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2219206A4 for ; Mon, 27 Apr 2020 11:41:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="fMxf9o9n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727782AbgD0Llv (ORCPT ); Mon, 27 Apr 2020 07:41:51 -0400 Received: from lelv0142.ext.ti.com ([198.47.23.249]:54092 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726907AbgD0Llp (ORCPT ); Mon, 27 Apr 2020 07:41:45 -0400 Received: from lelv0265.itg.ti.com ([10.180.67.224]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 03RBffL2013333; Mon, 27 Apr 2020 06:41:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1587987701; bh=pa3J4XQ5Erz+YsjPUom6zR5EcfQGkjqMNLYq1dzlDmY=; h=Subject:To:References:From:Date:In-Reply-To; b=fMxf9o9nAlVKqkJL0m0k0nAPeavwPckk59gQOUpabW/p8S21hdkm5CuGorHASsNDb 5K6tDUBnWDr9vhVk1OZ7r7IlAQ3yvqA85ZnRYKTrCKeCjLgJriihQ62RiqiRZV6duR b6utx9JRNygshhSFeyDSa5hMq1lQwgzvDLK5mJFw= Received: from DFLE105.ent.ti.com (dfle105.ent.ti.com [10.64.6.26]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 03RBffCY027427 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 27 Apr 2020 06:41:41 -0500 Received: from DFLE103.ent.ti.com (10.64.6.24) by DFLE105.ent.ti.com (10.64.6.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Mon, 27 Apr 2020 06:41:41 -0500 Received: from lelv0326.itg.ti.com (10.180.67.84) by DFLE103.ent.ti.com (10.64.6.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Mon, 27 Apr 2020 06:41:41 -0500 Received: from [127.0.0.1] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 03RBfcPU058972; Mon, 27 Apr 2020 06:41:39 -0500 Subject: Re: [PATCH 2/3] arm64: dts: ti: k3-j721e-main.dtsi: Add DSS node To: Tomi Valkeinen , Jyri Sarha , Nishanth Menon , Rob Herring , , , References: <20200422091512.950-1-tomi.valkeinen@ti.com> <20200422091512.950-2-tomi.valkeinen@ti.com> <47b7f858-a8d9-1c3b-4dca-2cc493f6730f@ti.com> <217c0c14-f4fb-7321-9f57-205df0cd01fe@ti.com> <9a4b1d0a-c871-2280-8d22-196730e9385b@ti.com> <3eb05f6d-523f-f7e5-a0e9-d47b852fe079@ti.com> From: Tero Kristo Message-ID: <6427a827-9175-75ab-72fb-a62a21795bf3@ti.com> Date: Mon, 27 Apr 2020 14:41:37 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <3eb05f6d-523f-f7e5-a0e9-d47b852fe079@ti.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 27/04/2020 14:37, Tomi Valkeinen wrote: > On 27/04/2020 14:15, Tomi Valkeinen wrote: >> On 27/04/2020 14:10, Jyri Sarha wrote: >>> On 27/04/2020 13:51, Tomi Valkeinen wrote: >>>> On 27/04/2020 13:37, Jyri Sarha wrote: >>>>> On 27/04/2020 13:09, Tero Kristo wrote: >>>>>>> +        status = "disabled"; >>>>>> >>>>>> Again, why disabled by default? >>>>>> >>>>> >>>>> tidss device is not functional without a defined video-port. The >>>>> driver >>>>> is not implemented in a way that it would handle a broken >>>>> configuration >>>>> gracefully. >>>> >>>> Then we need to fix it. The driver should handle the case where there >>>> are no ports defined just fine. >>>> >>> >>> Just by reading the code, I would say that currently the probe would >>> fail with returned -ENOMEM after calling drm_vblank_init() with zero >>> CRTCs. >>> >>> So should the probe fail gracefully and silently, or should we try to >>> register a DRM device with no CRTCs? Is that even possible? >> >> My first thought is that the driver should exit probe silently with >> ENODEV if there are no outputs defined (but, of course, with >> EPROBE_DEFER if there are outputs which haven't been probed yet). >> >> It gets a bit more complex if we ever support writeback, as that can >> be used as mem-to-mem without any displays, but I think we can ignore >> that for now. > > In any case, that's not the reason for status = "disabled", so that > discussion is not related to these patches as such. > > The reason to have DSS disabled is just to prevent pointless driver > probing. When a board dts or a DT overlay adds a display, the DSS DT > node has to be modified anyway to add the DT graph and the panel/bridge > data. So one can as well add the single line of "status = enabled" there. Ok, thanks for the explanation, queued all three patches towards 5.8 based on that. -Tero -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki