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 AD38BFEEF49 for ; Tue, 7 Apr 2026 14:54:05 +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:In-Reply-To:References:Cc: Subject:From:To:Message-Id:Date:Content-Type:Content-Transfer-Encoding: Mime-Version:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=dFpKKgJSe3LDnkGc1FYdedAaRZnlCAUJQ/ukxoYtD4Y=; b=B0LgMT2ytH088iU0ZdV0mJiuSu HL9TFC1E6BIjzFwKOv01mV+oQ6SeE1eAB4eDmoRM7l9Ch3Id2jnrlyYqkhIMreE+QopT+C6qrZaoy C4TAj33padGv6mv5aV4Uf/BHrF7ENqxBGDVkXVG/PwtTY2ymsMC+LZSqxa1yAS+D/4dUxIy9alVuM Tq2sxGuelhvknsPxwQiVJd8AjOYGJza88cnOUp83Zo5jAvYaMKpeMzBN4flYf2stleOaLR2DbWVw6 AVqL3UYmWya4wIiU3v0EmE4YtIgSc8mQLQU15ynkQjDRG52arGzggaaV9rcMSl0xEp+gNEdGBQRFQ vmcnm4dQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wA7oV-00000006ebL-2yZv; Tue, 07 Apr 2026 14:53:59 +0000 Received: from smtpout-02.galae.net ([185.246.84.56]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wA7oT-00000006eaS-07pW for linux-arm-kernel@lists.infradead.org; Tue, 07 Apr 2026 14:53:58 +0000 Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id A24D41A31C6; Tue, 7 Apr 2026 14:53:53 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 74AD7603C7; Tue, 7 Apr 2026 14:53:53 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id E190010450234; Tue, 7 Apr 2026 16:53:41 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1775573631; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=dFpKKgJSe3LDnkGc1FYdedAaRZnlCAUJQ/ukxoYtD4Y=; b=jyg5zU1hYNkpXLJb6meqXDq8VXWt5eBi1yf3MaMX4NsBnSaVC/ZPYaTPMHOcbkpkgn7seX HdjHcw4PrpZ0PYHJ18lCo/NHNq/wkP2Ku+QULqsv8pSWhETT/KsLi7kQeTcjZWYThxn7Q4 l7zHJtiDTJiJlC1CO/bQDYp8BnlXkGJuxUHCWCez3KNaNT6ICV89h3x6N65jZYF6dnuQhC xOEOeYuOK/aBMpBgzW0JucXrgPsddZzoiqseZiqilL5Fht5CfhYh8s8Bs8eo05cTOYj83O phfnzk8yElIsP6clYK1BZPlnI0lWTWcda3nfyaoQG1wnb5XiWHJf1bmTtOtIUA== Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 07 Apr 2026 16:53:40 +0200 Message-Id: To: "Damon Ding" , , , , , , , , , , , , , From: "Luca Ceresoli" Subject: Re: [PATCH v1 2/4] drm/bridge: dw-hdmi: Allow &dw_hdmi_plat_data.output_port = 0 without DRM_BRIDGE_ATTACH_NO_CONNECTOR Cc: , , , , , , , , , , X-Mailer: aerc 0.20.1 References: <20260403070032.447102-1-damon.ding@rock-chips.com> <20260403070032.447102-3-damon.ding@rock-chips.com> In-Reply-To: <20260403070032.447102-3-damon.ding@rock-chips.com> X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260407_075357_234114_290D358D X-CRM114-Status: GOOD ( 19.60 ) 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 Hello Damon, On Fri Apr 3, 2026 at 9:00 AM CEST, Damon Ding wrote: > In the previous commit, Luca split the dw-hdmi attach process into two > cases: > > A. hdmi->plat_data->output_port =3D 0: > the HDMI output (port@1) in device tree is not used > > B. hdmi->plat_data->output_port =3D 1: > the HDMI output (port@1) is parsed to find the next bridge > > For Rockchip, many older platforms (RK3288, RK3399, etc.) only support > case A by default. They can support DRM_BRIDGE_ATTACH_NO_CONNECTOR flag > after adapting to the bridge connector helper. Relax this constraint in > preparation for Rockchip dw-hdmi bridge-connector adaptation. > > Link: https://lore.kernel.org/all/20260402-drm-lcdif-dbanc-v3-6-27cd247a0= 847@bootlin.com/ > Signed-off-by: Damon Ding > --- > drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/= bridge/synopsys/dw-hdmi.c > index dd50dda3a4f5..20b2f9e145b0 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > @@ -2912,9 +2912,8 @@ static int dw_hdmi_bridge_attach(struct drm_bridge = *bridge, > { > struct dw_hdmi *hdmi =3D bridge->driver_private; > > - /* DRM_BRIDGE_ATTACH_NO_CONNECTOR requires a remote-endpoint to the nex= t bridge */ > - if (WARN_ON((flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) && !hdmi->plat_dat= a->output_port)) > - return -EINVAL; > + if ((flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) && !hdmi->plat_data->outpu= t_port) > + return 0; > > if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) { > struct device_node *remote __free(device_node) =3D My understanding is that a hdmi-connector node is required in DT when using drm_bridge_connector and DRM_BRIDGE_ATTACH_NO_CONNECTOR. Among others, it is necessary to expose the correct connector type instead of defaulting to DRM_MODE_CONNECTOR_HDMIA. @Dmitry, others, can you confirm or deny the above? If I'm correct, then the right way to support DRM_BRIDGE_ATTACH_NO_CONNECTOR here is adding an hdmi-connector node in DT, perhaps reusing the device tree overlay I proposed in [0]. [0] https://lore.kernel.org/lkml/20260407-drm-lcdif-dbanc-v4-8-247a16e61ef9= @bootlin.com/ Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com