[PATCH v.3 11/12] DRM/i915: Add bit field to record which pins have received HPD events (v3)

[Egbert Eich <eich@suse.de>]

This way it is possible to limit 're'-detect() of displays to connectors
which have received an HPD event.

v2: Reordered drm_i915_private: Move hpd_event_bits to hpd state tracking.
v3: Fix patch.

Signed-off-by: Egbert Eich <eich@suse.de>
---
 drivers/gpu/drm/i915/i915_drv.h |    1 +
 drivers/gpu/drm/i915/i915_irq.c |   47 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1fb7c44..d48d1e6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -933,6 +933,7 @@ typedef struct drm_i915_private {
 			HPD_MARK_DISABLED = 2
 		} hpd_mark;
 	} hpd_stats[HPD_NUM_PINS];
+	u32 hpd_event_bits;
 #define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
 	struct timer_list hotplug_reenable_timer;
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index fd68b21..9e8d5b4 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -330,6 +330,24 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
 						     crtc);
 }
 
+/**
+ * drm_helper_hpd_irq_single_connector_event() - call this function with mode_config.mutex lock held
+ */
+
+static int intel_hpd_irq_single_connector_event(struct drm_device *dev, struct drm_connector *connector)
+{
+	enum drm_connector_status old_status;
+
+	old_status = connector->status;
+
+	connector->status = connector->funcs->detect(connector, false);
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
+		      connector->base.id,
+		      drm_get_connector_name(connector),
+		      old_status, connector->status);
+	return (old_status != connector->status);
+}
+
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
@@ -344,6 +362,8 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_connector *connector;
 	unsigned long irqflags;
 	bool connector_disabled = false;
+	bool changed = false;
+	u32 hpd_event_bits;
 
 	/* HPD irq before everything is fully set up. */
 	if (!dev_priv->enable_hotplug_processing)
@@ -353,6 +373,9 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	hpd_event_bits = dev_priv->hpd_event_bits;
+	dev_priv->hpd_event_bits = 0;
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
 		intel_connector = to_intel_connector(connector);
 		intel_encoder = intel_connector->encoder;
@@ -366,6 +389,10 @@ static void i915_hotplug_work_func(struct work_struct *work)
 				| DRM_CONNECTOR_POLL_DISCONNECT;
 			connector_disabled = true;
 		}
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
+				      drm_get_connector_name(connector), intel_encoder->hpd_pin);
+		}
 	}
 	if (connector_disabled) {
 		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
@@ -375,14 +402,20 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
-	list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
-		if (intel_encoder->hot_plug)
-			intel_encoder->hot_plug(intel_encoder);
-
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		intel_connector = to_intel_connector(connector);
+		intel_encoder = intel_connector->encoder;
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			if (intel_encoder->hot_plug)
+				intel_encoder->hot_plug(intel_encoder);
+			if (intel_hpd_irq_single_connector_event(dev, connector))
+				changed = true;
+		}
+	}
 	mutex_unlock(&mode_config->mutex);
 
-	/* Just fire off a uevent and let userspace tell us what to do */
-	drm_helper_hpd_irq_event(dev);
+	if (changed)
+		drm_kms_helper_hotplug_event(dev);
 }
 
 static void ironlake_handle_rps_change(struct drm_device *dev)
@@ -620,12 +653,14 @@ static inline bool hotplug_irq_storm_detect(struct drm_device *dev,
 	for (i = 1; i < HPD_NUM_PINS; i++) {
 		if ((hpd[i] & hotplug_trigger) &&
 		    dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
+			dev_priv->hpd_event_bits |= (1 << i);
 			if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
 			    jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
 				dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
 				dev_priv->hpd_stats[i].hpd_cnt = 0;
 			} else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
 				dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
+				dev_priv->hpd_event_bits &= ~(1 << i);
 				DRM_DEBUG_KMS("HPD interrupt storm detected on  PIN %d\n", i);
 				ret = true;
 			} else
-- 
1.7.7