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 499D7C021A8 for ; Sat, 14 Sep 2024 19:13:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XphoZOg6kiH+O9OMvs/LfL3EJdtkYOrv3aE+MBYMnTI=; b=q28r23d3aFgdwNbEVySTl7YFke GYPv+uIhQ+2WhxKiX0Sy4vl1bkxDBsMe/VOQniD5Z0swAd0JepjKCW5uYJJasd/5/ztdeOc7fEM5y 9GUSRagp8Q3Ndqz8AwUwptPI0MT8jLM0YFMIcVT4lUu5Qvh1rASrbdEmVPcJlWOZ4Y4TQAZ+bMWPI 8Wjsf6RihCAfgJMGUYk5x+BAll/kKtVlJ5CfPT7eVLCUndvCCqtB7ULOvUnz5RqcA0pAER3umcGoL DCl3NABI96vD9ymODbeWEUGf9ysHZKP7y2nP/dwyPE2ndc2pdzX+wgnif9idc1sPiAPibwjV8FFx8 rk2Dndww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1spYDF-000000019ZS-2a7I; Sat, 14 Sep 2024 19:13:41 +0000 Received: from bali.collaboradmins.com ([2a01:4f8:201:9162::2]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1spYCA-000000019S1-1J6u; Sat, 14 Sep 2024 19:12:36 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1726341150; bh=PHZHrVw10h99rYEQdEFbDtMypLDFs11UWr5JxLxSJxc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ZsfJFGSYVsRNIwiMZkbPX4u3316vZoyqdoN5oaoIHurdx8PORAWYwKCaI2Ya8Eq7j ZjUPDFuoAbXYO5f0MqVNQv9EbaBriNnVCJGKtLRoTSnqokcQtdczHiTVDdYaON+JBn xXTjY/+IzgYlZ4Au5t9dzm/XMV5E1YiowMkGvd0eNkOR3RksqGoTPmIB3ArhvC6qSN ml4C7jyy2TVNCU8VQ6+Ab45XU8dGK+JRHbl1K9NB0djtMIe6YxB+zg532IXMId9oyL KtEVWAMO8FHw1ahJg2fILKtgdSFo/Gx63i4FEjrKaqA6FNmDAtTFjPVBSWpcdoBJFv CBvYulvUh0Ycw== Received: from [192.168.1.90] (unknown [188.27.55.48]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: cristicc) by bali.collaboradmins.com (Postfix) with ESMTPSA id 1122E17E3612; Sat, 14 Sep 2024 21:12:30 +0200 (CEST) Message-ID: Date: Sat, 14 Sep 2024 22:12:29 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 1/3] drm/bridge: synopsys: Add DW HDMI QP TX Controller support library To: Maxime Ripard Cc: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Daniel Vetter , Sandy Huang , =?UTF-8?Q?Heiko_St=C3=BCbner?= , Andy Yan , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Mark Yao , Sascha Hauer , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, devicetree@vger.kernel.org, kernel@collabora.com, Alexandre ARNOUD , Luis de Arquer , Algea Cao References: <20240906-b4-rk3588-bridge-upstream-v6-0-a3128fb103eb@collabora.com> <20240906-b4-rk3588-bridge-upstream-v6-1-a3128fb103eb@collabora.com> <20240909-horned-congenial-curassow-ebc5fa@houat> Content-Language: en-US From: Cristian Ciocaltea In-Reply-To: <20240909-horned-congenial-curassow-ebc5fa@houat> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240914_121234_562049_CB79F16E X-CRM114-Status: GOOD ( 17.28 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Maxime, On 9/9/24 6:13 PM, Maxime Ripard wrote: > Hi, > > On Fri, Sep 06, 2024 at 04:17:40AM GMT, Cristian Ciocaltea wrote: >> +static enum drm_connector_status >> +dw_hdmi_qp_bridge_detect(struct drm_bridge *bridge) >> +{ >> + struct dw_hdmi_qp *hdmi = bridge->driver_private; >> + enum drm_connector_status status; >> + >> + status = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data); >> + >> + dev_dbg(hdmi->dev, "%s conn=%d scramb=%d\n", __func__, >> + status == connector_status_connected, hdmi->scramb_enabled); >> + >> + if (hdmi->scramb_enabled) { >> + cancel_delayed_work_sync(&hdmi->scramb_work); >> + >> + if (status == connector_status_connected) >> + dw_hdmi_qp_check_and_set_scramb(hdmi); >> + } >> + >> + return status; >> +} > > Unfortunately, that won't work. The HDMI Spec has (HDMI 2.0, Section > 6.1.3.1 - Scrambling Control): > > The minimum time period between the write to the Scrambling_Enable bit, > and the transmission of a scrambled video signal is not specified; > however the Source shall not begin transmission of a scrambled video > signal before writing a 1 to the Scrambling_Enable bit. The maximum time > period between the write to the Scrambling_Enable bit and the > transmission of a scrambled video signal shall be 100 ms. > > So you need to disable the output and enable it again. > > vc4 does just that, you can have a look here: > https://elixir.bootlin.com/linux/v6.10.9/source/drivers/gpu/drm/vc4/vc4_hdmi.c#L410 Thanks for all the details and references! Unfortunately I had to drop the scrambling setup for now [1], as I encountered some issues while attempting to get this implemented as suggested. Will get back to this and submit it separately when done. Regards, Cristian [1] https://lore.kernel.org/lkml/20240914-b4-rk3588-bridge-upstream-v7-0-2b1348137123@collabora.com/