1 files changed, 96 insertions, 2 deletions

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 251bc0e3b5e..8ac7fbf6b2b 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -257,6 +257,9 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
 
 	INIT_LIST_HEAD(&priv->lhead);
 	INIT_LIST_HEAD(&priv->fbs);
+	INIT_LIST_HEAD(&priv->event_list);
+	init_waitqueue_head(&priv->event_wait);
+	priv->event_space = 4096; /* set aside 4k for event buffer */
 
 	if (dev->driver->driver_features & DRIVER_GEM)
 		drm_gem_open(dev, priv);
@@ -413,6 +416,30 @@ static void drm_master_release(struct drm_device *dev, struct file *filp)
 	}
 }
 
+static void drm_events_release(struct drm_file *file_priv)
+{
+	struct drm_device *dev = file_priv->minor->dev;
+	struct drm_pending_event *e, *et;
+	struct drm_pending_vblank_event *v, *vt;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+
+	/* Remove pending flips */
+	list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link)
+		if (v->base.file_priv == file_priv) {
+			list_del(&v->base.link);
+			drm_vblank_put(dev, v->pipe);
+			v->base.destroy(&v->base);
+		}
+
+	/* Remove unconsumed events */
+	list_for_each_entry_safe(e, et, &file_priv->event_list, link)
+		e->destroy(e);
+
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+}
+
 /**
  * Release file.
  *
@@ -451,6 +478,8 @@ int drm_release(struct inode *inode, struct file *filp)
 	if (file_priv->minor->master)
 		drm_master_release(dev, filp);
 
+	drm_events_release(file_priv);
+
 	if (dev->driver->driver_features & DRIVER_GEM)
 		drm_gem_release(dev, file_priv);
 
@@ -544,9 +573,74 @@ int drm_release(struct inode *inode, struct file *filp)
 }
 EXPORT_SYMBOL(drm_release);
 
-/** No-op. */
+static bool
+drm_dequeue_event(struct drm_file *file_priv,
+		  size_t total, size_t max, struct drm_pending_event **out)
+{
+	struct drm_device *dev = file_priv->minor->dev;
+	struct drm_pending_event *e;
+	unsigned long flags;
+	bool ret = false;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+
+	*out = NULL;
+	if (list_empty(&file_priv->event_list))
+		goto out;
+	e = list_first_entry(&file_priv->event_list,
+			     struct drm_pending_event, link);
+	if (e->event->length + total > max)
+		goto out;
+
+	file_priv->event_space += e->event->length;
+	list_del(&e->link);
+	*out = e;
+	ret = true;
+
+out:
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+	return ret;
+}
+
+ssize_t drm_read(struct file *filp, char __user *buffer,
+		 size_t count, loff_t *offset)
+{
+	struct drm_file *file_priv = filp->private_data;
+	struct drm_pending_event *e;
+	size_t total;
+	ssize_t ret;
+
+	ret = wait_event_interruptible(file_priv->event_wait,
+				       !list_empty(&file_priv->event_list));
+	if (ret < 0)
+		return ret;
+
+	total = 0;
+	while (drm_dequeue_event(file_priv, total, count, &e)) {
+		if (copy_to_user(buffer + total,
+				 e->event, e->event->length)) {
+			total = -EFAULT;
+			break;
+		}
+
+		total += e->event->length;
+		e->destroy(e);
+	}
+
+	return total;
+}
+EXPORT_SYMBOL(drm_read);
+
 unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait)
 {
-	return 0;
+	struct drm_file *file_priv = filp->private_data;
+	unsigned int mask = 0;
+
+	poll_wait(filp, &file_priv->event_wait, wait);
+
+	if (!list_empty(&file_priv->event_list))
+		mask |= POLLIN | POLLRDNORM;
+
+	return mask;
 }
 EXPORT_SYMBOL(drm_poll);