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

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -4070,14 +4070,16 @@ static int intel_hdmi_reset_link(struct intel_encoder *encoder,
 	return modeset_pipe(&crtc->base, ctx);
 }
 
-static bool intel_ddi_hotplug(struct intel_encoder *encoder,
-			      struct intel_connector *connector)
+static enum intel_hotplug_state
+intel_ddi_hotplug(struct intel_encoder *encoder,
+		  struct intel_connector *connector,
+		  bool irq_received)
 {
 	struct drm_modeset_acquire_ctx ctx;
-	bool changed;
+	enum intel_hotplug_state state;
 	int ret;
 
-	changed = intel_encoder_hotplug(encoder, connector);
+	state = intel_encoder_hotplug(encoder, connector, irq_received);
 
 	drm_modeset_acquire_init(&ctx, 0);
 
@@ -4099,7 +4101,7 @@ static bool intel_ddi_hotplug(struct intel_encoder *encoder,
 	drm_modeset_acquire_fini(&ctx);
 	WARN(ret, "Acquiring modeset locks failed with %i\n", ret);
 
-	return changed;
+	return state;
 }
 
 static struct intel_connector *

drivers/gpu/drm/i915/display/intel_dp.c

@@ -4863,14 +4863,16 @@ int intel_dp_retrain_link(struct intel_encoder *encoder,
  * retrain the link to get a picture. That's in case no
  * userspace component reacted to intermittent HPD dip.
  */
-static bool intel_dp_hotplug(struct intel_encoder *encoder,
-			     struct intel_connector *connector)
+static enum intel_hotplug_state
+intel_dp_hotplug(struct intel_encoder *encoder,
+		 struct intel_connector *connector,
+		 bool irq_received)
 {
 	struct drm_modeset_acquire_ctx ctx;
-	bool changed;
+	enum intel_hotplug_state state;
 	int ret;
 
-	changed = intel_encoder_hotplug(encoder, connector);
+	state = intel_encoder_hotplug(encoder, connector, irq_received);
 
 	drm_modeset_acquire_init(&ctx, 0);
 
@@ -4889,7 +4891,7 @@ static bool intel_dp_hotplug(struct intel_encoder *encoder,
 	drm_modeset_acquire_fini(&ctx);
 	WARN(ret, "Acquiring modeset locks failed with %i\n", ret);
 
-	return changed;
+	return state;
 }
 
 static void intel_dp_check_service_irq(struct intel_dp *intel_dp)

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;
@@ -279,15 +282,15 @@ 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,
 		      connector->base.name,
 		      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);
@@ -373,23 +380,47 @@ 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);
 	mutex_unlock(&dev->mode_config.mutex);
 
 	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);
 }

drivers/gpu/drm/i915/display/intel_hotplug.h

@@ -15,8 +15,9 @@ struct intel_connector;
 struct intel_encoder;
 
 void intel_hpd_poll_init(struct drm_i915_private *dev_priv);
-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);
 void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 			   u32 pin_mask, u32 long_mask);
 void intel_hpd_init(struct drm_i915_private *dev_priv);

drivers/gpu/drm/i915/display/intel_sdvo.c

@@ -1921,12 +1921,14 @@ static void intel_sdvo_enable_hotplug(struct intel_encoder *encoder)
 			     &intel_sdvo->hotplug_active, 2);
 }
 
-static bool intel_sdvo_hotplug(struct intel_encoder *encoder,
-			       struct intel_connector *connector)
+static enum intel_hotplug_state
+intel_sdvo_hotplug(struct intel_encoder *encoder,
+		   struct intel_connector *connector,
+		   bool irq_received)
 {
 	intel_sdvo_enable_hotplug(encoder);
 
-	return intel_encoder_hotplug(encoder, connector);
+	return intel_encoder_hotplug(encoder, connector, irq_received);
 }
 
 static bool

drivers/gpu/drm/i915/i915_debugfs.c

@@ -4071,7 +4071,7 @@ static int i915_hpd_storm_ctl_show(struct seq_file *m, void *data)
 	 */
 	intel_synchronize_irq(dev_priv);
 	flush_work(&dev_priv->hotplug.dig_port_work);
-	flush_work(&dev_priv->hotplug.hotplug_work);
+	flush_delayed_work(&dev_priv->hotplug.hotplug_work);
 
 	seq_printf(m, "Threshold: %d\n", hotplug->hpd_storm_threshold);
 	seq_printf(m, "Detected: %s\n",

drivers/gpu/drm/i915/i915_drv.h

@@ -163,7 +163,7 @@ enum hpd_pin {
 #define HPD_STORM_DEFAULT_THRESHOLD 50
 
 struct i915_hotplug {
-	struct work_struct hotplug_work;
+	struct delayed_work hotplug_work;
 
 	struct {
 		unsigned long last_jiffies;
@@ -175,6 +175,7 @@ struct i915_hotplug {
 		} state;
 	} stats[HPD_NUM_PINS];
 	u32 event_bits;
+	u32 retry_bits;
 	struct delayed_work reenable_work;
 
 	u32 long_port_mask;

drivers/gpu/drm/i915/intel_drv.h

@@ -101,14 +101,21 @@ struct intel_fbdev {
 	struct mutex hpd_lock;
 };
 
+enum intel_hotplug_state {
+	INTEL_HOTPLUG_UNCHANGED,
+	INTEL_HOTPLUG_CHANGED,
+	INTEL_HOTPLUG_RETRY,
+};
+
 struct intel_encoder {
 	struct drm_encoder base;
 
 	enum intel_output_type type;
 	enum port port;
 	unsigned int cloneable;
-	bool (*hotplug)(struct intel_encoder *encoder,
-			struct intel_connector *connector);
+	enum intel_hotplug_state (*hotplug)(struct intel_encoder *encoder,
+					    struct intel_connector *connector,
+					    bool irq_received);
 	enum intel_output_type (*compute_output_type)(struct intel_encoder *,
 						      struct intel_crtc_state *,
 						      struct drm_connector_state *);