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 22A7BC433EF for ; Mon, 20 Dec 2021 10:49:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229845AbhLTKtC (ORCPT ); Mon, 20 Dec 2021 05:49:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34406 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229823AbhLTKtC (ORCPT ); Mon, 20 Dec 2021 05:49:02 -0500 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4F76C06173E for ; Mon, 20 Dec 2021 02:49:01 -0800 (PST) Received: by mail-wr1-x42f.google.com with SMTP id s1so19229459wrg.1 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=0LVL4pAW7KD5K4+k//C3eC2LuYssZ6pIz2JjFuQaHz9Zuz34lnc8ZBrupiLmdQvt6y HTz+LOCFWeoIbBuyB+lWWdXkTAQcqsnS+kRBrfjgRnaQBMw+idEMohpOMKELpwSpKvZI 7AkkZNbihQBQXCC6eY/aaGas6Cqg4qxQF5kii+FIO87VqYCXGrOhHb6FiUj7bxyDa6y6 cMnb03Kzy98q0W75eNEGmvhz/KqEcPvU7QUdzEJLW4A3vPNjSRfcnpZ1ezlCgazAdV0B TmiwlT9AmRP23Kh+NTfA8/Gvj4FHGQ9wT6BnpDtq/ZRfOCOgIp47SszXUJQHpoB/Donc epLw== X-Gm-Message-State: AOAM533NSwkff5o/oX3BdPJMN499jofUOLOQtLjDzwOcJY1cDm4XywII 3GMkX4jFbQkq27sX2E2ncGI= 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 Cc: Dmitry Osipenko , Thomas Graichen , Douglas Anderson , Laurent Pinchart , Jon Hunter , dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org 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 Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org 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