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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 3E571C71133 for ; Fri, 25 Aug 2023 12:02:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=HM1dAGfuRTWXEe1ZtuRMoHOUOPLSncgFW5JQX0Q5HKA=; b=2HkduB2KrRk7IW EvoTOWewQ1RLiLuwTQD7XETwamr5JLkr4oksvILuEBmfF6i3DBS5G5UiGcw4OxfrvJTULguj/P6Yn WmVjl1GFaadA4rTAFecnuGrHi/BYx8ElEL4KrkxOZuv2VA4wFKKHMZLdnoHCHSs8TSd1H6xuyrB4P pyMnhsj0zVYNcVgDefwsggDcGYDCVm8v+FTtFRC4gYJisYQsuLcKdvydCLvFgHdGtjHQuUFZDINqo Oqq8IyV5C01tjCRH82EqYHbG/OtYHJmVJW0dZAUuxdJNq368HENcJhDXg1b4cXoKvPgquR6vU0nKt 8jsqEx1Og5YyfNFGZFEw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qZVVM-005KSY-0w; Fri, 25 Aug 2023 12:01:32 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qZVVI-005KRe-2F; Fri, 25 Aug 2023 12:01:30 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C97166323D; Fri, 25 Aug 2023 12:01:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 043B1C433C8; Fri, 25 Aug 2023 12:01:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692964886; bh=DkaQY49NCfEp3URelzQqFMcnMc9cI/W/Kd4KxUDsdP8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kpxFzYXNwWgfxY8NNYJlMX4BJy36WR3HvNPFBufzFvuc+1G+3dkUXzrHL7ecq6mrA S+KFw5hGxzStAZDEnRnBk4WifvWMZuoZBBrcmgn/Dn9+zQa078bUaJyvGrejf9V6X5 RWyFIhHXbppXCO/spDu7kvAEYcLk29nfQ88Rm6z74iJbixllna1t3ik3LHDEt+IONO iesMsfH9UMEvHZ6Z21UZ1aTtRRKDc85QPw8bHHYeUViA3BA3OwHDK67vDf5tgiYaUx 0I7ShYr0Jd6zDxGifpdP/+pP3ynXQg+ReQY+kywslBe73Q49XNTLzNZqZDjulJNQ1w NBTKCDVjyc/KQ== From: Michael Walle To: angelogioacchino.delregno@collabora.com Cc: airlied@gmail.com, amergnat@baylibre.com, chunkuang.hu@kernel.org, ck.hu@mediatek.com, daniel@ffwll.ch, dri-devel@lists.freedesktop.org, ehristev@collabora.com, kernel@collabora.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com, nfraprado@collabora.com, p.zabel@pengutronix.de, wenst@chromium.org, Michael Walle Subject: Re: [PATCH v7 09/11] drm/mediatek: dp: Add support for embedded DisplayPort aux-bus Date: Fri, 25 Aug 2023 14:01:09 +0200 Message-Id: <20230825120109.3132209-1-mwalle@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230725073234.55892-10-angelogioacchino.delregno@collabora.com> References: <20230725073234.55892-10-angelogioacchino.delregno@collabora.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230825_050129_347978_692497F2 X-CRM114-Status: GOOD ( 23.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi AngeloGioacchino, > For the eDP case we can support using aux-bus on MediaTek DP: this > gives us the possibility to declare our panel as generic "panel-edp" > which will automatically configure the timings and available modes > via the EDID that we read from it. > > To do this, move the panel parsing at the end of the probe function > so that the hardware is initialized beforehand and also initialize > the DPTX AUX block and power both on as, when we populate the > aux-bus, the panel driver will trigger an EDID read to perform > panel detection. > > Last but not least, since now the AUX transfers can happen in the > separated aux-bus, it was necessary to add an exclusion for the > cable_plugged_in check in `mtk_dp_aux_transfer()` and the easiest > way to do this is to simply ignore checking that when the bridge > type is eDP. This patch breaks my board based on the MT8195 which only has one DisplayPort output port. I suspect it might also break the mt8195-cherry board. While the mediatek-dpi driver finds the DP port: [ 3.131645] mediatek-dpi 1c113000.dp-intf: Found bridge node: /soc/dp-tx@1c600000 The probing of the eDP is deferred: [ 13.289009] platform 1c015000.dp-intf: deferred probe pending So I don't know why, but to make dp_intf1 work, it seems that dp_intf0 must be probed successfully. After this patch, the edp (which is connected to the dp_intf1) probe will return with an -ENODEV and the previous call to devm_drm_bridge_add() will be rolled back. Before this patch, bridge_add() was called in any case (in the error case with next_bridge = NULL) and the mediatek-dpi probed like that: [ 3.121011] mediatek-dpi 1c015000.dp-intf: Found bridge node: /soc/edp-tx@1c500000 [ 3.122111] mediatek-dpi 1c113000.dp-intf: Found bridge node: /soc/dp-tx@1c600000 Eventually resulting in a framebuffer device: [ 4.451081] mediatek-drm mediatek-drm.8.auto: [drm] fb0: mediatekdrmfb frame buffer device NB, somehow this series broke the initial display output. I always have to replug the DisplayPort to get some output. I'll dig deeper into that later. .. > @@ -2519,21 +2553,14 @@ static int mtk_dp_probe(struct platform_device *pdev) > return dev_err_probe(dev, mtk_dp->irq, > "failed to request dp irq resource\n"); > > - mtk_dp->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0); > - if (IS_ERR(mtk_dp->next_bridge) && > - PTR_ERR(mtk_dp->next_bridge) == -ENODEV) > - mtk_dp->next_bridge = NULL; In my case, this branch was taken. -michael > - else if (IS_ERR(mtk_dp->next_bridge)) > - return dev_err_probe(dev, PTR_ERR(mtk_dp->next_bridge), > - "Failed to get bridge\n"); > - > ret = mtk_dp_dt_parse(mtk_dp, pdev); > if (ret) > return dev_err_probe(dev, ret, "Failed to parse dt\n"); > > - drm_dp_aux_init(&mtk_dp->aux); > mtk_dp->aux.name = "aux_mtk_dp"; > + mtk_dp->aux.dev = dev; > mtk_dp->aux.transfer = mtk_dp_aux_transfer; > + drm_dp_aux_init(&mtk_dp->aux); > > spin_lock_init(&mtk_dp->irq_thread_lock); > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel