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 2AE46C433F5 for ; Thu, 27 Jan 2022 10:32:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239508AbiA0Kc5 (ORCPT ); Thu, 27 Jan 2022 05:32:57 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:50236 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239571AbiA0Kcx (ORCPT ); Thu, 27 Jan 2022 05:32:53 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: kholk11) with ESMTPSA id C6C341F44FF6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1643279572; bh=3IabDGDX1X8Lt5ZJt6EaeuvYuynxAJ9WYVmwg7VmWFI=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=A+56cwLIlE83emP51k58CylI86F66rWP4M+qdLmNZZXsyQsc/rk7rAaw9cQ9GfzN2 NFg1ESq9RvxlhQuPqpZ83YpsLZus80W1ZC+B03U52ypPP8BL6wO3m32ed7gnMgJ2g/ hYfaG3ddeF05kmu1TeS4zl1baGU/pyAENVuy6BHej1ROueYVRX5rOB06JdZgobg954 3KMh+vmTcgCJdQBuNDcBUqT/aVC2iPZdL/6ZFD6RBQYPJZsXyGW6fomKu+HiEwa3tL uZcaLZLdxBXNXqKu4XmBlgD7wBnMkkbqvI163A8FUnXoM2gQ27qBysJBPxG+n1bS1O Flfp/NL33MO7Q== Subject: Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge To: Jagan Teki Cc: dri-devel@lists.freedesktop.org, chunkuang.hu@kernel.org, airlied@linux.ie, linux-kernel@vger.kernel.org, andrzej.hajda@intel.com, linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com, kernel@collabora.com, linux-arm-kernel@lists.infradead.org References: <20220104095954.10313-1-angelogioacchino.delregno@collabora.com> From: AngeloGioacchino Del Regno Message-ID: <4b46b8ce-7300-ef42-eb17-efd87ebdf773@collabora.com> Date: Thu, 27 Jan 2022 11:32:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 12/01/22 08:09, Jagan Teki ha scritto: > On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno > wrote: >> >> DRM bridge drivers are now attaching their DSI device at probe time, >> which requires us to register our DSI host in order to let the bridge >> to probe: this recently started producing an endless -EPROBE_DEFER >> loop on some machines that are using external bridges, like the >> parade-ps8640, found on the ACER Chromebook R13. >> >> Now that the DSI hosts/devices probe sequence is documented, we can >> do adjustments to the mtk_dsi driver as to both fix now and make sure >> to avoid this situation in the future: for this, following what is >> documented in drm_bridge.c, move the mtk_dsi component_add() to the >> mtk_dsi_ops.attach callback and delete it in the detach callback; >> keeping in mind that we are registering a drm_bridge for our DSI, >> which is only used/attached if the DSI Host is bound, it wouldn't >> make sense to keep adding our bridge at probe time (as it would >> be useless to have it if mtk_dsi_ops.attach() fails!), so also move >> that one to the dsi host attach function (and remove it in detach). >> >> Signed-off-by: AngeloGioacchino Del Regno >> Reviewed-by: Andrzej Hajda >> --- > > Eventually I've observed similar issue on other Component based DSI > controllers, hence > > Reviewed-by: Jagan Teki > Hello dri-devel, can you please pick this patch? All MediaTek platforms are broken in v5.17 without this one. Thanks, Angelo