[PATCH v4 1/3] drm: Introduce a new connector status

[Marius Vlad <marius.vlad@collabora.com>]

Introduce a new boolean variable used to track connector's
connect/disconnect status and it is being used on both polling and the
HPD (Hot Plug Detect) paths.

A subsequent change would make use of this connector status to propagate
per-connector udev hotplug events.

The connector status is set in the drm_connector_funcs.fill_modes and
cleared out when firing out KMS uevents.

Allows user-space to receive the connector's ID, rather than having a
generic hot-plug event for all connectors, or in the HPD path, just the
first one found with a connection status change.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
---
 drivers/gpu/drm/drm_connector.c    |  1 +
 drivers/gpu/drm/drm_probe_helper.c | 17 +++++++++++++++++
 drivers/gpu/drm/drm_sysfs.c        |  1 +
 include/drm/drm_connector.h        |  3 +++
 4 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 272d6254ea47..3c6628ee3096 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->status_changed = 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..f0474368e98d 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -629,6 +629,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 			mod_delayed_work(system_wq,
 					 &dev->mode_config.output_poll_work,
 					 0);
+
+		connector->status_changed = true;
 	}
 
 	/*
@@ -732,6 +734,17 @@ 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->status_changed = 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 +761,10 @@ void drm_kms_helper_connector_hotplug_event(struct drm_connector *connector)
 {
 	struct drm_device *dev = connector->dev;
 
+	mutex_lock(&dev->mode_config.mutex);
+	connector->status_changed = false;
+	mutex_unlock(&dev->mode_config.mutex);
+
 	drm_sysfs_connector_hotplug_event(connector);
 	drm_client_dev_hotplug(dev);
 }
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index b01ffa4d6509..bd9161490116 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -199,6 +199,7 @@ static ssize_t status_store(struct device *device,
 		return ret;
 
 	old_force = connector->force;
+	connector->status_changed = true;
 
 	if (sysfs_streq(buf, "detect"))
 		connector->force = 0;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 8f34f4b8183d..e4310df3d55c 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -2146,6 +2146,9 @@ struct drm_connector {
 	/** @force: a DRM_FORCE_<foo> state for forced mode sets */
 	enum drm_connector_force force;
 
+	/** @status_changed: if the old status doesn't match current connection status */
+	bool status_changed;
+
 	/**
 	 * @edid_override: Override EDID set via debugfs.
 	 *
-- 
2.47.2