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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A681C433EF for ; Wed, 22 Dec 2021 03:02:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238411AbhLVDCB (ORCPT ); Tue, 21 Dec 2021 22:02:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235520AbhLVDCB (ORCPT ); Tue, 21 Dec 2021 22:02:01 -0500 Received: from mail-lj1-x22e.google.com (mail-lj1-x22e.google.com [IPv6:2a00:1450:4864:20::22e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E563BC061574 for ; Tue, 21 Dec 2021 19:02:00 -0800 (PST) Received: by mail-lj1-x22e.google.com with SMTP id z8so1422769ljz.9 for ; Tue, 21 Dec 2021 19:02:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=wm8Yrjopy492NzBpwSLQqPTvQKvPN3l++wypA+HZ4RM=; b=bHDnYR/sWzK8MlejMHmG8ZP3MQw94YJocF0LJxZDftfxzek6egth5iHoPAfvzP1jn6 5kFjdSmOp/5zVsngRvIbOsM3wKNVDLZK6vOQ93D0beEwusrIb0uMx8rXfWx/Z9GXpgL6 Uhfu9nmYOz3GE8+PKrRpLuFhjTy4w3uMbyrA2DILtI1N4G6DP80OFeBQuS7PaoiVVpJ8 IfyTudE+hinFjZOjTLwV91Y9cm2bw4kl32BJpIzuBoW9llB3S5NOlxFCeaPkRW8NGR3r g6vOpgS4Z/Q0CsxW3Lu6ucoa6FM8AtuDa/CS6nN7dCz0qhNV3ZsRNx/IDNjAQMsXpaDF Ou6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=wm8Yrjopy492NzBpwSLQqPTvQKvPN3l++wypA+HZ4RM=; b=vmfAFMayVwFVnNl05/d7i/SZD72QNAhVPzhV8a1TrfyOOQS+mu0Z9DiAtQXmS95Uu6 eOAhCAb/ZvvKQnuvzMzucQ5z3hQh9J/Eqid6DSMrnrv/oeicXbUxoy6d8fvHmIAwdHv7 5yX4s4unFBqwoU2kprr58ijhy14K+0PmSfIDExOLmR9V2Vt/8IvAcZmv1ruFKJDBmsh1 q+FdeNCAyPSnd9i0TVcpkJXICFFGx7/X9c2N9MPwF0AYHn0tb+gNigjBCjP3fTN+wWXR cy3yNQin9KXYiOKtXW+V7SiLK+XwxDf0AfCr0j5KxiVaUBUrAxfd0DuCW7L7VULnJdUi j4GQ== X-Gm-Message-State: AOAM531mRSuBcaz/5hFiwKW+YMCpyVjFFdWD3jw1oktBmsOhZ31imyip BZF8DIHiF3KR0kQno+aiTAaBuey0h+g= X-Google-Smtp-Source: ABdhPJxCT//IyPAiErDmM1GSo+PvEhwRPRkyQCnsGkSIqFHRx2PINwIgMXpkXffBhnscqmnudZfvQw== X-Received: by 2002:a2e:3304:: with SMTP id d4mr820939ljc.377.1640142118858; Tue, 21 Dec 2021 19:01:58 -0800 (PST) Received: from [192.168.2.145] (46-138-43-24.dynamic.spd-mgts.ru. [46.138.43.24]) by smtp.googlemail.com with ESMTPSA id g22sm71912lfr.237.2021.12.21.19.01.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 21 Dec 2021 19:01:58 -0800 (PST) Subject: Re: [PATCH 0/2] drm/tegra: Fix panel support on Venice 2 and Nyan To: Thierry Reding Cc: Thomas Graichen , Douglas Anderson , Laurent Pinchart , Jon Hunter , dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org References: <20211220104855.428290-1-thierry.reding@gmail.com> <1bac3b32-ad9b-4d10-c7fb-6aafd353cdd4@gmail.com> From: Dmitry Osipenko Message-ID: Date: Wed, 22 Dec 2021 06:01:26 +0300 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: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org 21.12.2021 21:01, Thierry Reding пишет: > On Tue, Dec 21, 2021 at 07:45:31PM +0300, Dmitry Osipenko wrote: >> 21.12.2021 19:17, Thierry Reding пишет: >>> On Tue, Dec 21, 2021 at 06:47:31PM +0300, Dmitry Osipenko wrote: >>>> 21.12.2021 13:58, Thierry Reding пишет: >>>> .. >>>>>>>> The panel->ddc isn't used by the new panel-edp driver unless panel is >>>>>>>> compatible with "edp-panel". Hence the generic_edp_panel_probe() should >>>>>>>> either fail or crash for a such "edp-panel" since panel->ddc isn't fully >>>>>>>> instantiated, AFAICS. >>>>>>> >>>>>>> I've tested this and it works fine on Venice 2. Since that was the >>>>>>> reference design for Nyan, I suspect that Nyan's will also work. >>>>>>> >>>>>>> It'd be great if Thomas or anyone else with access to a Nyan could >>>>>>> test this to verify that. >>>>>> >>>>>> There is no panel-edp driver in the v5.15. The EOL of v5.15 is Oct, >>>>>> 2023, hence we need to either use: >>>>> >>>>> All the (at least relevant) functionality that is in panel-edp was in >>>>> panel-simple before it was moved to panel-edp. I've backported this set >>>>> of patches to v5.15 and it works just fine there. >>>> >>>> Will we be able to add patch to bypass the panel's DT ddc-i2c-bus on >>>> Nyan to keep the older DTBs working? >>> >>> I don't see why we would want to do that. It's quite clear that the DTB >>> is buggy in this case and we have a more accurate way to describe what's >>> really there in hardware. In addition that more accurate representation >>> also gets rid of a bug. Obviously because the bug is caused by the >>> previous representation that was not accurate. >>> >>> Given that we can easily replace the DTBs on these devices there's no >>> reason to make this any more complicated than it has to be. >> >> Don't you care about normal people at all? Do you assume that everyone >> must to be a kernel developer to be able to use Tegra devices? :/ > > If you know how to install a custom kernel you also know how to replace > the DTB on these devices. > > For everyone else, once these patches are merged upstream and > distributions start shipping the new version, they will get this > automatically by updating their kernel package since most distributions > actually ship the DTB files as part of that. > >> It's not a problem for you to figure out why display is broken, for >> other people it's a problem. Usually nobody will update DTB without a >> well known reason, instead device will be dusted on a shelf. In the end >> you won't have any users at all. > > Most "normal" people aren't even going to notice that their DTB is going > to be updated. They would actually have to do extra work *not* to update > it. My past experience tells that your assumption is incorrect. There are quite a lot of people who will update kernel, but not DTB. ARM devices have endless variations of bootloaders and individual quirks required for a successful installation of a kernel. Kernel update by distro usually isn't a thing on ARM.