[Intel-gfx] [RFC 14/15] drm/i915/hdmi21/mtl: Add support for sending uevent to user for FRL training failure

[Ankit Nautiyal <ankit.k.nautiyal@intel.com>]

In case of HDMI2.1 FRL training failure for a given mode, the user
should be sent a uevent signalling Link failure.

This patch adds support for sending uevent to userspace in case of link
training failure.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdmi.c | 30 +++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 1eadf77dc819..9e8ee6d5bc5d 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2944,6 +2944,31 @@ void intel_infoframe_init(struct intel_digital_port *dig_port)
 	}
 }
 
+/* Common code with DP, need to put in a common place */
+static void intel_hdmi_modeset_retry_work_fn(struct work_struct *work)
+{
+	struct intel_connector *intel_connector;
+	struct drm_connector *connector;
+
+	intel_connector = container_of(work, typeof(*intel_connector),
+				       modeset_retry_work);
+	connector = &intel_connector->base;
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
+		      connector->name);
+
+	/* Grab the locks before changing connector property*/
+	mutex_lock(&connector->dev->mode_config.mutex);
+	/*
+	 * Set connector link status to BAD and send a Uevent to notify
+	 * userspace to do a modeset.
+	 */
+	drm_connector_set_link_status_property(connector,
+					       DRM_MODE_LINK_STATUS_BAD);
+	mutex_unlock(&connector->dev->mode_config.mutex);
+	/* Send Hotplug uevent so userspace can reprobe */
+	drm_kms_helper_hotplug_event(connector->dev);
+}
+
 void intel_hdmi_init_connector(struct intel_digital_port *dig_port,
 			       struct intel_connector *intel_connector)
 {
@@ -3021,6 +3046,11 @@ void intel_hdmi_init_connector(struct intel_digital_port *dig_port,
 					   &conn_info);
 	if (!intel_hdmi->cec_notifier)
 		drm_dbg_kms(&dev_priv->drm, "CEC notifier get failed\n");
+
+	/* Initialize the work for modeset in case of link train failure */
+	if (DISPLAY_VER(dev_priv) >= 14)
+		INIT_WORK(&intel_connector->modeset_retry_work,
+			  intel_hdmi_modeset_retry_work_fn);
 }
 
 /*
-- 
2.25.1