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 22FB0F34C51 for ; Mon, 13 Apr 2026 12:26:20 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1FFEA10E42A; Mon, 13 Apr 2026 12:26:17 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=bootlin.com header.i=@bootlin.com header.b="hxpi7Dsx"; dkim-atps=neutral Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0183A10E011 for ; Thu, 9 Apr 2026 17:08:53 +0000 (UTC) Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 4AD721A324E; Thu, 9 Apr 2026 17:08:52 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 00587603E4; Thu, 9 Apr 2026 17:08:51 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id B8770104500F2; Thu, 9 Apr 2026 19:08:41 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1775754530; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding; bh=vkWOcKx6uUnLGWEeSpSMD8GMbN5TDhNOCyHUzp+VpLg=; b=hxpi7DsxOvnrGkGEMd+Aa5L7+cTR44o6q+DIIYM+E88DF08NNiyGSA36Z9B4uTkPe9PTf3 Y1Mk2/KNjvIiSUnjp+GTl2o32jI/r0soNWm+SBkJliCgN3BwZxRrxdFL58Hk5UBNyxxU66 o+th6eHU1A4yNEroonMDElx+4JgdLv68aWDmEACMzOD1Xf7fT9k/ovMBns/p6sTn+D53D5 l7gP3O7x9X7kwvGIhScbDAZh4NjOCoYvale6z4mrsLdOhSQuGo7Ka7dpGxuFmJhyLYlxXv 2XEYp9Ki+p27ZZgvpeUgFNv70GwDkdOH64xkmoWbfBfPWMfBPLAuprjOnPcl3g== From: Kory Maincent Subject: [PATCH RFC 00/12] Add support for DisplayPort link training information report Date: Thu, 09 Apr 2026 19:08:16 +0200 Message-Id: <20260409-feat_link_cap-v1-0-7069e8199ce2@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-B4-Tracking: v=1; b=H4sIAADd12kC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDIzMDIyMz3bTUxJL4nMy87PjkxAJdI4PkpCSzNGPDFBMDJaCegqLUtMwKsHn RSkFuzkqxtbUAHOP6R2QAAAA= To: Jani Nikula , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , David Airlie , Simona Vetter , Dave Airlie , Jesse Barnes , Eric Anholt , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Chun-Kuang Hu , Philipp Zabel , Matthias Brugger , AngeloGioacchino Del Regno , Chris Wilson Cc: Thomas Petazzoni , Mark Yacoub , Sean Paul , Louis Chauvet , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Simona Vetter , Kory Maincent X-Mailer: b4 0.14-dev-d4707 X-Last-TLS-Session-Version: TLSv1.3 X-Mailman-Approved-At: Mon, 13 Apr 2026 12:26:15 +0000 X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" DisplayPort link training negotiates the physical-layer parameters needed for a reliable connection: lane count, link rate, voltage swing, pre-emphasis, and optionally Display Stream Compression (DSC). Currently, each driver exposes this state in its own way, often through driver-specific debugfs entries, with no standard interface for userspace diagnostic and monitoring tools. This series introduces a generic, DRM-managed framework for exposing DP link training state as standard connector properties, modeled after the existing HDMI helper drmm_connector_hdmi_init(). The new drmm_connector_dp_init() helper initializes a DP connector and registers the following connector properties to expose the negotiated link state to userspace: - num_lanes: negotiated lane count (1, 2 or 4) - link_rate: negotiated link rate - dsc_en: whether Display Stream Compression is active - voltage_swingN: per-lane voltage swing level (lanes 0-3) - pre_emphasisN: per-lane pre-emphasis level (lanes 0-3) Two runtime helpers update and clear these properties when link training completes or the link goes down: - drm_connector_dp_set_link_train_properties() - drm_connector_dp_reset_link_train_properties() Two drivers are updated as reference implementations: i915 (direct connector path) and MediaTek (via the bridge connector framework using a new DRM_BRIDGE_OP_DP flag). The i915 patches are preceded by a series of conversions to DRM managed resources, which are required before adopting drmm_connector_dp_init(). The MST case in i915 driver is not supported yet. Patches 1-3: Fix two error-path cleanup bugs in i915 sdvo and lvds [Will probably be sent standalone] Patches 4-8: Convert i915 display resources to DRM managed lifetime Patch 9: Introduce the core drmm_connector_dp_init() framework Patch 10: Wire the i915 DP connector to use the new helpers Patch 11: Introduce DRM_BRIDGE_OP_DP and wire bridge connectors Patch 12: Wire the MediaTek DP bridge to the new helpers [untested] Signed-off-by: Kory Maincent --- Kory Maincent (12): drm/i915/display/intel_sdvo: Fix double connector destroy in error paths drm/i915/display/intel_lvds: Drop redundant manual cleanup on init failure drm/i915/display/intel_dp: Drop redundant intel_dp_aux_fini() on init failure drm/i915/display: Switch to drmm_mode_config_init() and drop manual cleanup drm/i915/display: Switch to managed for crtc drm/i915/display: Switch to managed for plane drm/i915/display: Switch to managed for encoder drm/i915/display: Switch to managed for connector drm: Introduce drmm_connector_dp_init() with link training state properties drm/i915/display/dp: Adopt dp_connector helpers to expose link training state drm/bridge: Wire drmm_connector_dp_init() via new DRM_BRIDGE_OP_DP flag drm/mediatek: Use dp_connector helpers to report link training state drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/display/drm_bridge_connector.c | 26 +- drivers/gpu/drm/drm_dp_connector.c | 344 +++++++++++++++++++++ drivers/gpu/drm/i915/display/g4x_dp.c | 39 +-- drivers/gpu/drm/i915/display/g4x_hdmi.c | 27 +- drivers/gpu/drm/i915/display/i9xx_plane.c | 97 +++--- drivers/gpu/drm/i915/display/icl_dsi.c | 50 ++- drivers/gpu/drm/i915/display/intel_connector.c | 26 +- drivers/gpu/drm/i915/display/intel_connector.h | 5 +- drivers/gpu/drm/i915/display/intel_crt.c | 28 +- drivers/gpu/drm/i915/display/intel_crtc.c | 102 +++--- drivers/gpu/drm/i915/display/intel_cursor.c | 41 ++- drivers/gpu/drm/i915/display/intel_ddi.c | 64 ++-- drivers/gpu/drm/i915/display/intel_display.c | 8 - drivers/gpu/drm/i915/display/intel_display.h | 1 - .../gpu/drm/i915/display/intel_display_driver.c | 37 ++- drivers/gpu/drm/i915/display/intel_dp.c | 43 ++- .../gpu/drm/i915/display/intel_dp_link_training.c | 25 ++ drivers/gpu/drm/i915/display/intel_dp_mst.c | 33 +- drivers/gpu/drm/i915/display/intel_dvo.c | 43 +-- drivers/gpu/drm/i915/display/intel_encoder.c | 6 +- drivers/gpu/drm/i915/display/intel_encoder.h | 3 +- drivers/gpu/drm/i915/display/intel_hdmi.c | 15 +- drivers/gpu/drm/i915/display/intel_lvds.c | 45 ++- drivers/gpu/drm/i915/display/intel_plane.c | 45 +-- drivers/gpu/drm/i915/display/intel_plane.h | 5 +- drivers/gpu/drm/i915/display/intel_sdvo.c | 134 +++----- drivers/gpu/drm/i915/display/intel_sprite.c | 119 ++++--- drivers/gpu/drm/i915/display/intel_tv.c | 26 +- drivers/gpu/drm/i915/display/skl_universal_plane.c | 102 +++--- drivers/gpu/drm/i915/display/vlv_dsi.c | 42 +-- drivers/gpu/drm/mediatek/mtk_dp.c | 34 +- include/drm/drm_bridge.h | 13 + include/drm/drm_connector.h | 38 +++ include/drm/drm_dp_connector.h | 109 +++++++ 35 files changed, 1125 insertions(+), 651 deletions(-) --- base-commit: db5a75cfd29766536be62aece9f19c6e7a858fa6 change-id: 20260226-feat_link_cap-20cbb6f31d40 Best regards, -- Köry Maincent, Bootlin Embedded Linux and kernel engineering https://bootlin.com