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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 22B7CC53219 for ; Tue, 28 Jul 2026 13:09:09 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9350910E585; Tue, 28 Jul 2026 13:09:08 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="CKmqcV/4"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 70D1A10E585 for ; Tue, 28 Jul 2026 13:09:06 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 073694126C; Tue, 28 Jul 2026 13:09:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B42361F000E9; Tue, 28 Jul 2026 13:09:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785244145; bh=rLUY2nqmr5gNrh5OtGeN1PUrcISwt92MZoBlcThllVM=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=CKmqcV/49WeACj1GKQjYEbHn/wmefzPg22J1p73JM8SnZr+1UOvNnl3/Zk/pbwZwG WxUnum7Y8BO7JB8vwZDHjiJ0nVZwJRNp7tM/A62cvcGLHoQnEnx3d5DeyNLa5xwT16 8tcc3gXebVLjLolvJ4oI7Tj7nfr/XAxF2vlmZnvQp/42ZSuodhzlMiUjrMphSwe7Z0 YOpkyYGrQz2QU0EaQSd05yeoHZ6+P00MR4OciRQT97EYCXrUhn+sKuxsDJfUoBp3h5 v2K0+/Rl+5VMLFPzi7IkqLJUnyTH4NisD46cqeOiA44xR9GIP6ANvgH9Ne+RiP/UfO asssRjFN9SzPw== From: sashiko-bot@kernel.org Subject: Re: [PATCH v5 1/2] dt-bindings: display: bridge: cdns, mhdp8546: Add no-hpd property to the cadence bridge To: "Yashas D" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20260728125336.776116-2-y-d@ti.com> References: <20260728125336.776116-1-y-d@ti.com> <20260728125336.776116-2-y-d@ti.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 28 Jul 2026 13:09:05 +0000 Message-Id: <20260728130905.B42361F000E9@smtp.kernel.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] The `no-hpd` property is documented in the device tree bindings = but has no corresponding implementation in the driver. -- --- Patch [1]: [PATCH v5 1/2] dt-bindings: display: bridge: cdns, mhdp8546:= Add no-hpd property to the cadence bridge --- commit 4ac60fbbcafba148711703269045306014cd935a Author: Rahul T R dt-bindings: display: bridge: cdns, mhdp8546: Add no-hpd property to the ca= dence bridge This commit introduces the no-hpd property to the mhdp8546 device tree bindings. It provides a way to indicate when the hardware HPD line is not available, specifying that the driver should fall back to auxiliary channel DPCD reads for hotplug detection. > diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,mhdp85= 46.yaml b/Documentation/devicetree/bindings/display/bridge/cdns,mhdp8546.ya= ml > --- a/Documentation/devicetree/bindings/display/bridge/cdns,mhdp8546.yaml > +++ b/Documentation/devicetree/bindings/display/bridge/cdns,mhdp8546.yaml [ ... ] > @@ -57,6 +57,23 @@ properties: > interrupts: > maxItems: 1 > =20 > + no-hpd: > + type: boolean > + description: > + Set if the HPD line on the bridge isn't physically connected to the > + DisplayPort connector or cannot be used for hotplug detection. > + > + Valid use cases include: > + - HPD pin not routed to the connector on the PCB > + - HPD signal muxed with another function (e.g., audio) on the SoC, > + making it unavailable for hotplug detection > + - Hardware design where HPD cannot reliably detect monitor presence > + > + When this property is set, the driver will use auxiliary channel (= AUX) > + DPCD reads to detect monitor connection instead of relying on the > + hardware HPD signal. Monitor detection will use polling rather than > + interrupt-driven detection. > + [Severity: Medium] Is the driver implementation missing for this new property? The binding documentation states that the driver will use polling rather th= an interrupt-driven detection when this property is set. However, looking at t= he driver in cdns_mhdp_probe(), it unconditionally requires hardware HPD operations: drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c:cdns_mhdp_probe() { ... mhdp->bridge.of_node =3D pdev->dev.of_node; mhdp->bridge.ops =3D DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_HPD; mhdp->bridge.type =3D DRM_MODE_CONNECTOR_DisplayPort; ... } Does the driver need logic to parse the no-hpd property and conditionally adjust these operations to enable polling instead of enforcing hardware HPD? > ports: > $ref: /schemas/graph.yaml#/properties/ports > --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260728125336.7761= 16-1-y-d@ti.com?part=3D1