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 59ADBCD5BC8 for ; Tue, 26 May 2026 10:20:34 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AEA2C10E186; Tue, 26 May 2026 10:20:33 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="fivFZDl1"; dkim-atps=neutral Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9E4C710E186 for ; Tue, 26 May 2026 10:20:32 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; t=1779790826; cv=none; d=zohomail.com; s=zohoarc; b=WVeKtsK3w3GiySd0N2NFtZVTGtPFVDc53tjDDjjSlE8NcjxmHz2BogEJzW6SUEp2T2VhWroulGCJ57LlRK3W/l15gp5wjtiwPjP1hDUqIMfN7cozXex3zwr1eDng/mXRb0GBDcHo/jTBWAlyhp8v8/xxBl3tYEI4MdxEeOdvoFA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1779790826; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=h3ONQKNZedByi4cctJEY3O+tdeJyYQGllqWFhAoyvcQ=; b=QdCf9I8x0Jdz75NtLjh4aJGrFfjUanXhmx3i3vJ1sA4czpV8PUR5aSV0ct0nkPoDkfzluY4ejC+ieZH2guqT6wpnd3+gngr9RDUnWzPlG4x7hRf4ihhVoMI9vjqyF0ZsGFvTwhGrGCsLwSJUacJQCav4TtzyCj6MXbUPEA2H5eM= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1779790826; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Subject:Subject:Date:Date:Message-Id:Message-Id:MIME-Version:Content-Type:Content-Transfer-Encoding:To:To:Cc:Cc:Reply-To; bh=h3ONQKNZedByi4cctJEY3O+tdeJyYQGllqWFhAoyvcQ=; b=fivFZDl1GddsvdAFDocU8q+xZ6Ytuk+nRteo4jOjbxPvVEyypEorsOz9628mQf+A cTRCbcE/SlpSCwIx+0FwyQpVEaomXRJtaUB+WaZU508Y++xxhVCwW1d2a/O1oWrUr+Q uEpp2ja4WvFh6g0T6E/AO58T6wauf1DznihtW2Dc= Received: by mx.zohomail.com with SMTPS id 1779790823862385.29510544553034; Tue, 26 May 2026 03:20:23 -0700 (PDT) From: Nicolas Frattaroli Subject: [PATCH v3 0/4] Add SCDC information to connector debugfs Date: Tue, 26 May 2026 12:19:56 +0200 Message-Id: <20260526-scdc-link-health-v3-0-59e4a4aaead1@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAAAAAAAC/22OzW7CMBCEXyXymS3+IcFw4j2qHhx70ywkMdgmA qG8e02IVKnltBrtzDfzYBEDYWT74sECjhTJD1moVcFsa4ZvBHJZM8llxTdCQbTOQkfDCVo0XWp B71R+CeV2lWU5dg7Y0G1Gfn69dLzWR7TpyVkcAS/X3JVeNlabiGB931PaFy70kOi8Xi57QlqKy Yf7PHMUc2ZZVP5fNArgoHGrBGqNpuEH67vO1D6Yj1wyA0f5CyklfwORGVIKYRqhras29V/INE0 /L3DQLD4BAAA= X-Change-ID: 20260413-scdc-link-health-89326013d96c To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Daniel Stone Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, Nicolas Frattaroli , Daniel Stone X-Mailer: b4 0.15.2 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" HDMI uses the DDC I2C bus for communicating various bits of link status out of band with the actual HDMI video signal. This information can be useful for debugging issues like questionable cables sabotaged by feline teeth, Enthusiast Grade cables made of cow fencing wire, and other such problems that ruin one's media viewing plans. Consequently, this series exposes various bits of pertinent information from the SCDC protocol in an HDMI connector's debugfs. To continually poll the link status, userspace can poll the debugfs file. --- Changes in v3: - Add patch to change return type of drm_scdc_read/write. - Rework error counter reading to duplicate less code. - Also check lane 3 counter valid flag when reading its error counter. - Use memset to clear buf for error counters, rather than doing it in the loop. - Make read_error_counters not accept 0 as num_lanes; fix it up in the caller instead. - Link to v2: https://patch.msgid.link/20260520-scdc-link-health-v2-0-511af18cd64b@collabora.com Changes in v2: - Add HDMI 2.1 SCDC status reporting - Link to v1: https://patch.msgid.link/20260415-scdc-link-health-v1-0-8e731e88eaf0@collabora.com To: Maarten Lankhorst To: Maxime Ripard To: Thomas Zimmermann To: David Airlie To: Simona Vetter To: Andrzej Hajda To: Neil Armstrong To: Robert Foss To: Laurent Pinchart To: Jonas Karlman To: Jernej Skrabec To: Luca Ceresoli To: Daniel Stone Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: kernel@collabora.com Signed-off-by: Nicolas Frattaroli --- Nicolas Frattaroli (4): drm/scdc-helper: Don't use ssize_t return type for scdc_read/write drm/scdc-helper: Add scdc_status debugfs entry drm/display: bridge_connector: init scdc debugfs for HDMI drm/scdc-helper: Implement parsing and printing HDMI 2.1 fields drivers/gpu/drm/display/drm_bridge_connector.c | 4 + drivers/gpu/drm/display/drm_scdc_helper.c | 358 ++++++++++++++++++++++++- include/drm/display/drm_scdc.h | 9 + include/drm/display/drm_scdc_helper.h | 121 ++++++++- 4 files changed, 484 insertions(+), 8 deletions(-) --- base-commit: 587c82eb2067eff6f13385e1b7cf49fc6c3febbc change-id: 20260413-scdc-link-health-89326013d96c Best regards, -- Nicolas Frattaroli