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 B9FABC982ED for ; Mon, 21 Sep 2026 16:06:06 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0C8A710E7B2; Mon, 21 Sep 2026 16:06:06 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="h1C+LHJF"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id 305DA10E75F for ; Mon, 21 Sep 2026 16:06:04 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 6692C60120; Mon, 21 Sep 2026 16:06:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F27341F000FF; Mon, 21 Sep 2026 16:06:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790006763; bh=SMwYUdLB3raEiZbaKeVWihIMk/iCUfNIfcV0SP67EAU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=h1C+LHJFW7Dj407o5YotRGPARx1SE3mj+KJlTruqQG6dRxYUnT+lAlXd+/0zsfiIG w/+yaXCTvOlHkkZIXl3vJ8tY9AyHur+TJ7hvTlRFKXjq5umvEMNASrbdh+MOa0q+0w 6wpWp0dm5BhW/VkwZimowkeOxbWbVHu3QnvRn9HZN48ac9TaCI/ZoQ1PTCfXLjVWAP egvPJlsJP2Rd/bZP8Yjz54HOWd/mb9m9DtovClJ7n45WHmUXLj792g6k8EWXXynWY+ jKE6DCVVBgcCsP4z/wm7rv+RAXPkuylSET7TwwXEb+bamWfWxHXuB6vaLz110t8pWY vqFNe+XJBdUAQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC 08/25] drm/bridge: synopsys: Add VTEM EMP support To: "Nicolas Frattaroli" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20260921-vrr-limiter-uapi-v1-8-2fcd7d011646@collabora.com> References: <20260921-vrr-limiter-uapi-v1-0-2fcd7d011646@collabora.com> <20260921-vrr-limiter-uapi-v1-8-2fcd7d011646@collabora.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 21 Sep 2026 16:06:02 +0000 Message-Id: <20260921160602.F27341F000FF@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] drm/bridge: synopsys: missing clear before updating VTEM EMP pac= ket -- commit f01e70b0b31bb2936c32cbd70054c3941b7363a9 Author: Derek Foreman drm/bridge: synopsys: Add VTEM EMP support Add code to pack and schedule VTEM EMPs. > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/d= rm/bridge/synopsys/dw-hdmi-qp.c > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c [ ... ] > @@ -775,6 +784,42 @@ static int dw_hdmi_qp_bridge_write_spd_infoframe(str= uct drm_bridge *bridge, > return 0; > } > =20 > +static int dw_hdmi_qp_bridge_write_vtem_emp(struct drm_bridge *bridge, > + const u8 *buffer, size_t len) > +{ > + struct dw_hdmi_qp *hdmi =3D bridge->driver_private; > + u32 val, i; > + > + if (len !=3D HDMI_INFOFRAME_SIZE(VTEM)) { > + dev_err(hdmi->dev, "unsupported vtem emp packet size of %zu\n", len); > + return -EINVAL; > + } > + > + val =3D buffer[1] << 8 | buffer[2] << 16; > + dw_hdmi_qp_write(hdmi, val, PKT_EMP_VTEM_CONTENTS0); [Severity: Medium] Should dw_hdmi_qp_bridge_clear_vtem_emp() be called here before writing the new packet contents to the hardware registers? The DRM HDMI state helper does not automatically call the clear function=20 before writing when updating an existing frame. Modifying the packet scheduler contents across multiple register writes while transmission is active might cause a hardware race condition, where the hardware could transmit a torn VTEM EMP packet containing a mix of old and new data. This could result in transient glitches or desynchronization in the sink's VRR state. Other infoframe writers in this driver, such as=20 dw_hdmi_qp_bridge_write_spd_infoframe(), explicitly call their respective clear functions before writing new contents. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260921-vrr-limite= r-uapi-v1-0-2fcd7d011646@collabora.com?part=3D8