linux-kernel - [PATCH v6 1/4] drm: Introduce pending_hp to drm

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Message-Id: <20260123-hot-plug-passup-v6-1-aaaf61d960bb@collabora.com>
Date: Fri, 23 Jan 2026 20:44:02 +0100
From: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
To: Ville Syrjälä <ville.syrjala@...ux.intel.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Louis Chauvet <louis.chauvet@...tlin.com>, 
 Haneen Mohammed <hamohammed.sa@...il.com>, 
 Melissa Wen <melissa.srw@...il.com>, 
 Daniel Stone <daniel.stone@...labora.com>, 
 Ian Forbes <ian.forbes@...adcom.com>, 
 Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 kernel@...labora.com, Nicolas Frattaroli <nicolas.frattaroli@...labora.com>, 
 Marius Vlad <marius.vlad@...labora.com>
Subject: [PATCH v6 1/4] drm: Introduce pending_hp to drm_connector

From: Marius Vlad <marius.vlad@...labora.com>

Introduce a new boolean variable used to track whether a connector has
changed its status since the last hotplug event for it was sent to
userspace. It is used by both the polling and HPD path.

A subsequent change will make use of this new member to propagate
per-connector udev hotplug events to userspace, rather than sending a
global hotplug event.

Signed-off-by: Marius Vlad <marius.vlad@...labora.com>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
---
 drivers/gpu/drm/drm_connector.c    |  1 +
 drivers/gpu/drm/drm_probe_helper.c | 17 +++++++++++++++++
 drivers/gpu/drm/drm_sysfs.c        |  2 ++
 include/drm/drm_connector.h        |  3 +++
 4 files changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 4f5b27fab475..aa8a187578da 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -274,6 +274,7 @@ static int drm_connector_init_only(struct drm_device *dev,
 
 	/* provide ddc symlink in sysfs */
 	connector->ddc = ddc;
+	connector->pending_hp = false;
 
 	INIT_LIST_HEAD(&connector->head);
 	INIT_LIST_HEAD(&connector->global_connector_list_entry);
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 09b12c30df69..91de34a25bf8 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -732,6 +732,17 @@ EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
  */
 void drm_kms_helper_hotplug_event(struct drm_device *dev)
 {
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+
+	mutex_lock(&dev->mode_config.mutex);
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		connector->pending_hp = false;
+	}
+	drm_connector_list_iter_end(&conn_iter);
+	mutex_unlock(&dev->mode_config.mutex);
+
 	drm_sysfs_hotplug_event(dev);
 	drm_client_dev_hotplug(dev);
 }
@@ -748,6 +759,10 @@ void drm_kms_helper_connector_hotplug_event(struct drm_connector *connector)
 {
 	struct drm_device *dev = connector->dev;
 
+	mutex_lock(&dev->mode_config.mutex);
+	connector->pending_hp = false;
+	mutex_unlock(&dev->mode_config.mutex);
+
 	drm_sysfs_connector_hotplug_event(connector);
 	drm_client_dev_hotplug(dev);
 }
@@ -837,6 +852,7 @@ static void output_poll_execute(struct work_struct *work)
 				    old_epoch_counter, connector->epoch_counter);
 
 			changed = true;
+			connector->pending_hp = true;
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);
@@ -1101,6 +1117,7 @@ bool drm_helper_hpd_irq_event(struct drm_device *dev)
 				first_changed_connector = connector;
 			}
 
+			connector->pending_hp = true;
 			changed++;
 		}
 	}
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index b01ffa4d6509..53076c2afd12 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -216,6 +216,8 @@ static ssize_t status_store(struct device *device,
 			    connector->base.id, connector->name,
 			    old_force, connector->force);
 
+		connector->pending_hp = true;
+
 		connector->funcs->fill_modes(connector,
 					     dev->mode_config.max_width,
 					     dev->mode_config.max_height);
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 7eaec37ae1c7..84968b2d967a 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -2191,6 +2191,9 @@ struct drm_connector {
 	/** @force: a DRM_FORCE_<foo> state for forced mode sets */
 	enum drm_connector_force force;
 
+	/** @pending_hp: true if connector changed since last hotplug event */
+	bool pending_hp;
+
 	/**
 	 * @edid_override: Override EDID set via debugfs.
 	 *

-- 
2.52.0