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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 58432C433FE for ; Mon, 20 Dec 2021 10:49:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 54B9D10F739; Mon, 20 Dec 2021 10:49:03 +0000 (UTC) Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by gabe.freedesktop.org (Postfix) with ESMTPS id C14E910F72E for ; Mon, 20 Dec 2021 10:49:01 +0000 (UTC) Received: by mail-wr1-x435.google.com with SMTP id q16so19156255wrg.7 for ; Mon, 20 Dec 2021 02:49:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=TNi4qiic0TYEzuXe3GMyw+hHwUv5aSbcIBy8T7yuN2I=; b=mWGJ0/BtFhEpiuWuq8qucQwyR7Lh0LI943aKEKwy7IFYuOSsxn0YcT2+5ilb6biX2D hwi91QZpD5ApdPzt+V8xc2ZU5VhjaV3Jns4drOsen+fTF4Paquai3TdZNYdNb1oA6ii0 OH/mEGZBjY7t2R7PLqPVrg5E90VEY6/GYNc3VgPp/YWKBRYs6AfZneCABnJzD3DWqwC+ 2h031q6Rb0GLhiP0Xv3OHOG6PxMhmqt0H81l91mdJdPW9j0wDGI+6r6ZD/sDPlAlxukn XR1i34z0m0+FpdSrnSP/6iK9LisgOM/FeYyDv/e9JCOVYKHyCy+ztPby9PSNeTxwxU1u msSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=TNi4qiic0TYEzuXe3GMyw+hHwUv5aSbcIBy8T7yuN2I=; b=vUljEG4Ke8tMwBgoxV8ZKC391xtKkKrHnaeBl8rPviIm5Xl7fovpA5dCAvsdkNi55n MGSCxfKuiYtH7JRcVUkGSj2nGodoAwN/0VtPpuY+cCPjUg0kkPz7Wklo55bmLVhL2uAB lpolaF6p/ZjPT6kJXkwM/2CEnb7m6zQrESiQpF4ac/kS1OppPC1WMFdAq6P2cJ6P2b+b sVJp95UtNDue4tWshWRLXdWwlNZfiMQ260tzujTYxQUKJlFWWt+jGj1U8CIwDvS+ATzt omJAlafi9DLC8mGsyvRjskh6ZwLOknBocjKqWyED7Hr0E8cEkN264t2xY5vU7eQXToG4 DKXA== X-Gm-Message-State: AOAM531mgzJsRpwTUSHESnUekFTR6bLGTOX+25sNv7MeoVGgCRSxf098 /UzJBIzgE+b6o8wy9gZMn/iio0WkzPrSOA== X-Google-Smtp-Source: ABdhPJx3FoxjltX3ZPqn0uII9LtxXbQ85gtyXIy0sPHbu3r4xcA9ae09kglW6+U8NyJB4owZljGF/w== X-Received: by 2002:adf:f68a:: with SMTP id v10mr12435876wrp.212.1639997340338; Mon, 20 Dec 2021 02:49:00 -0800 (PST) Received: from localhost ([193.209.96.43]) by smtp.gmail.com with ESMTPSA id bg34sm19534503wmb.47.2021.12.20.02.48.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Dec 2021 02:48:59 -0800 (PST) From: Thierry Reding To: Thierry Reding Subject: [PATCH 0/2] drm/tegra: Fix panel support on Venice 2 and Nyan Date: Mon, 20 Dec 2021 11:48:53 +0100 Message-Id: <20211220104855.428290-1-thierry.reding@gmail.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Graichen , Douglas Anderson , dri-devel@lists.freedesktop.org, Jon Hunter , Laurent Pinchart , linux-tegra@vger.kernel.org, Dmitry Osipenko Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Thierry Reding Hi, this is an alternative proposal to fix panel support on Venice 2 and Nyan. Dmitry had proposed a different solution that involved reverting the I2C/DDC registration order and would complicate things by breaking the encapsulation of the driver by introducing a global (though locally scoped) variable[0]. This set of patches avoids that by using the recently introduced DP AUX bus infrastructure. The result is that the changes are actually less intrusive and not a step back. Instead they nicely remove the circular dependency that previously existed and caused these issues in the first place. To be fair, this is not perfect either because it requires a device tree change and hence isn't technically backwards-compatible. However, given that the original device tree was badly broken in the first place, I think we can make an exception, especially since it is not generally a problem to update device trees on the affected devices. Secondly, this relies on infrastructure that was introduced in v5.15 and therefore will be difficult to backport beyond that. However, since this functionality has been broken since v5.13 and all of the kernel versions between that and v5.15 are EOL anyway, there isn't much that we can do to fix the interim versions anyway. Adding Doug and Laurent since they originally designed the AUX bus patches in case they see anything in here that would be objectionable. Thierry [0]: https://lore.kernel.org/dri-devel/20211130230957.30213-1-digetx@gmail.com/ Thierry Reding (2): drm/tegra: dpaux: Populate AUX bus ARM: tegra: Move panels to AUX bus arch/arm/boot/dts/tegra124-nyan-big.dts | 15 +++++++++------ arch/arm/boot/dts/tegra124-nyan-blaze.dts | 15 +++++++++------ arch/arm/boot/dts/tegra124-venice2.dts | 14 +++++++------- drivers/gpu/drm/tegra/Kconfig | 1 + drivers/gpu/drm/tegra/dpaux.c | 7 +++++++ 5 files changed, 33 insertions(+), 19 deletions(-) -- 2.34.1