drm/i915: Add support for retrying hotplug

There is some scenarios that we are aware that sink probe can fail,
so lets add the infrastructure to let hotplug() hook to request
another probe after some time.

v2: Handle shared HPD pins (Imre)
v3: Rebased
v4: Renamed INTEL_HOTPLUG_NOCHANGE to INTEL_HOTPLUG_UNCHANGED to keep
it consistent(Rodrigo)
v5: Making the working queue used explicit through all the callers to
hotplug_work (Ville)

Tested-by: Timo Aaltonen <tjaalton@ubuntu.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190712005343.24571-1-jose.souza@intel.com

1 files changed, 46 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
index ea3de4acc850..342587d91d57 100644
--- a/drivers/gpu/drm/i915/display/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
@@ -112,6 +112,7 @@ enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
 
 #define HPD_STORM_DETECT_PERIOD		1000
 #define HPD_STORM_REENABLE_DELAY	(2 * 60 * 1000)
+#define HPD_RETRY_DELAY			1000
 
 /**
  * intel_hpd_irq_storm_detect - gather stats and detect HPD IRQ storm on a pin
@@ -266,8 +267,10 @@ static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
 	intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
 }
 
-bool intel_encoder_hotplug(struct intel_encoder *encoder,
-			   struct intel_connector *connector)
+enum intel_hotplug_state
+intel_encoder_hotplug(struct intel_encoder *encoder,
+		      struct intel_connector *connector,
+		      bool irq_received)
 {
 	struct drm_device *dev = connector->base.dev;
 	enum drm_connector_status old_status;
@@ -279,7 +282,7 @@ bool intel_encoder_hotplug(struct intel_encoder *encoder,
 		drm_helper_probe_detect(&connector->base, NULL, false);
 
 	if (old_status == connector->base.status)
-		return false;
+		return INTEL_HOTPLUG_UNCHANGED;
 
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 		      connector->base.base.id,
@@ -287,7 +290,7 @@ bool intel_encoder_hotplug(struct intel_encoder *encoder,
 		      drm_get_connector_status_name(old_status),
 		      drm_get_connector_status_name(connector->base.status));
 
-	return true;
+	return INTEL_HOTPLUG_CHANGED;
 }
 
 static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
@@ -339,7 +342,7 @@ static void i915_digport_work_func(struct work_struct *work)
 		spin_lock_irq(&dev_priv->irq_lock);
 		dev_priv->hotplug.event_bits |= old_bits;
 		spin_unlock_irq(&dev_priv->irq_lock);
-		schedule_work(&dev_priv->hotplug.hotplug_work);
+		queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
 	}
 }
 
@@ -349,14 +352,16 @@ static void i915_digport_work_func(struct work_struct *work)
 static void i915_hotplug_work_func(struct work_struct *work)
 {
 	struct drm_i915_private *dev_priv =
-		container_of(work, struct drm_i915_private, hotplug.hotplug_work);
+		container_of(work, struct drm_i915_private,
+			     hotplug.hotplug_work.work);
 	struct drm_device *dev = &dev_priv->drm;
 	struct intel_connector *intel_connector;
 	struct intel_encoder *intel_encoder;
 	struct drm_connector *connector;
 	struct drm_connector_list_iter conn_iter;
-	bool changed = false;
+	u32 changed = 0, retry = 0;
 	u32 hpd_event_bits;
+	u32 hpd_retry_bits;
 
 	mutex_lock(&dev->mode_config.mutex);
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
@@ -365,6 +370,8 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	hpd_event_bits = dev_priv->hotplug.event_bits;
 	dev_priv->hotplug.event_bits = 0;
+	hpd_retry_bits = dev_priv->hotplug.retry_bits;
+	dev_priv->hotplug.retry_bits = 0;
 
 	/* Enable polling for connectors which had HPD IRQ storms */
 	intel_hpd_irq_storm_switch_to_polling(dev_priv);
@@ -373,16 +380,29 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	drm_connector_list_iter_begin(dev, &conn_iter);
 	drm_for_each_connector_iter(connector, &conn_iter) {
+		u32 hpd_bit;
+
 		intel_connector = to_intel_connector(connector);
 		if (!intel_connector->encoder)
 			continue;
 		intel_encoder = intel_connector->encoder;
-		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+		hpd_bit = BIT(intel_encoder->hpd_pin);
+		if ((hpd_event_bits | hpd_retry_bits) & hpd_bit) {
 			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
 				      connector->name, intel_encoder->hpd_pin);
 
-			changed |= intel_encoder->hotplug(intel_encoder,
-							  intel_connector);
+			switch (intel_encoder->hotplug(intel_encoder,
+						       intel_connector,
+						       hpd_event_bits & hpd_bit)) {
+			case INTEL_HOTPLUG_UNCHANGED:
+				break;
+			case INTEL_HOTPLUG_CHANGED:
+				changed |= hpd_bit;
+				break;
+			case INTEL_HOTPLUG_RETRY:
+				retry |= hpd_bit;
+				break;
+			}
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);
@@ -390,6 +410,17 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	if (changed)
 		drm_kms_helper_hotplug_event(dev);
+
+	/* Remove shared HPD pins that have changed */
+	retry &= ~changed;
+	if (retry) {
+		spin_lock_irq(&dev_priv->irq_lock);
+		dev_priv->hotplug.retry_bits |= retry;
+		spin_unlock_irq(&dev_priv->irq_lock);
+
+		mod_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work,
+				 msecs_to_jiffies(HPD_RETRY_DELAY));
+	}
 }
 
 
@@ -516,7 +547,7 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 	if (queue_dig)
 		queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
 	if (queue_hp)
-		schedule_work(&dev_priv->hotplug.hotplug_work);
+		queue_delayed_work(system_wq, &dev_priv->hotplug.hotplug_work, 0);
 }
 
 /**
@@ -636,7 +667,8 @@ void intel_hpd_poll_init(struct drm_i915_private *dev_priv)
 
 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 {
-	INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
+	INIT_DELAYED_WORK(&dev_priv->hotplug.hotplug_work,
+			  i915_hotplug_work_func);
 	INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
 	INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
 	INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
@@ -650,11 +682,12 @@ void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 	dev_priv->hotplug.long_port_mask = 0;
 	dev_priv->hotplug.short_port_mask = 0;
 	dev_priv->hotplug.event_bits = 0;
+	dev_priv->hotplug.retry_bits = 0;
 
 	spin_unlock_irq(&dev_priv->irq_lock);
 
 	cancel_work_sync(&dev_priv->hotplug.dig_port_work);
-	cancel_work_sync(&dev_priv->hotplug.hotplug_work);
+	cancel_delayed_work_sync(&dev_priv->hotplug.hotplug_work);
 	cancel_work_sync(&dev_priv->hotplug.poll_init_work);
 	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 }