drm: Add async event synchronization for drmWaitVblank
This patch adds a new flag to the drmWaitVblank ioctl, which asks the drm
to return immediately and notify userspace when the specified vblank sequence
happens by sending an event back on the drm fd.
The event mechanism works with the other flags supported by the ioctls,
specifically, the vblank sequence can be specified relatively or absolutely,
and works for primary and seconday crtc.
The signal field of the vblank request is used to provide user data,
which will be sent back to user space in the vblank event.
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 251bc0e..8ac7fbf 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -257,6 +257,9 @@
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_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 @@
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 @@
}
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);
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 0a6f0b3..72754ac 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -550,6 +550,62 @@
return ret;
}
+static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
+ union drm_wait_vblank *vblwait,
+ struct drm_file *file_priv)
+{
+ struct drm_pending_vblank_event *e;
+ struct timeval now;
+ unsigned long flags;
+ unsigned int seq;
+
+ e = kzalloc(sizeof *e, GFP_KERNEL);
+ if (e == NULL)
+ return -ENOMEM;
+
+ e->pipe = pipe;
+ e->event.base.type = DRM_EVENT_VBLANK;
+ e->event.base.length = sizeof e->event;
+ e->event.user_data = vblwait->request.signal;
+ e->base.event = &e->event.base;
+ e->base.file_priv = file_priv;
+ e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
+
+ do_gettimeofday(&now);
+ spin_lock_irqsave(&dev->event_lock, flags);
+
+ if (file_priv->event_space < sizeof e->event) {
+ spin_unlock_irqrestore(&dev->event_lock, flags);
+ kfree(e);
+ return -ENOMEM;
+ }
+
+ file_priv->event_space -= sizeof e->event;
+ seq = drm_vblank_count(dev, pipe);
+ if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
+ (seq - vblwait->request.sequence) <= (1 << 23)) {
+ vblwait->request.sequence = seq + 1;
+ }
+
+ DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
+ vblwait->request.sequence, seq, pipe);
+
+ e->event.sequence = vblwait->request.sequence;
+ if ((seq - vblwait->request.sequence) <= (1 << 23)) {
+ e->event.tv_sec = now.tv_sec;
+ e->event.tv_usec = now.tv_usec;
+ drm_vblank_put(dev, e->pipe);
+ list_add_tail(&e->base.link, &e->base.file_priv->event_list);
+ wake_up_interruptible(&e->base.file_priv->event_wait);
+ } else {
+ list_add_tail(&e->base.link, &dev->vblank_event_list);
+ }
+
+ spin_unlock_irqrestore(&dev->event_lock, flags);
+
+ return 0;
+}
+
/**
* Wait for VBLANK.
*
@@ -609,6 +665,9 @@
goto done;
}
+ if (flags & _DRM_VBLANK_EVENT)
+ return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
+
if ((flags & _DRM_VBLANK_NEXTONMISS) &&
(seq - vblwait->request.sequence) <= (1<<23)) {
vblwait->request.sequence = seq + 1;
@@ -641,6 +700,38 @@
return ret;
}
+void drm_handle_vblank_events(struct drm_device *dev, int crtc)
+{
+ struct drm_pending_vblank_event *e, *t;
+ struct timeval now;
+ unsigned long flags;
+ unsigned int seq;
+
+ do_gettimeofday(&now);
+ seq = drm_vblank_count(dev, crtc);
+
+ spin_lock_irqsave(&dev->event_lock, flags);
+
+ list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
+ if (e->pipe != crtc)
+ continue;
+ if ((seq - e->event.sequence) > (1<<23))
+ continue;
+
+ DRM_DEBUG("vblank event on %d, current %d\n",
+ e->event.sequence, seq);
+
+ e->event.sequence = seq;
+ e->event.tv_sec = now.tv_sec;
+ e->event.tv_usec = now.tv_usec;
+ drm_vblank_put(dev, e->pipe);
+ list_move_tail(&e->base.link, &e->base.file_priv->event_list);
+ wake_up_interruptible(&e->base.file_priv->event_wait);
+ }
+
+ spin_unlock_irqrestore(&dev->event_lock, flags);
+}
+
/**
* drm_handle_vblank - handle a vblank event
* @dev: DRM device
@@ -651,7 +742,11 @@
*/
void drm_handle_vblank(struct drm_device *dev, int crtc)
{
+ if (!dev->num_crtcs)
+ return;
+
atomic_inc(&dev->_vblank_count[crtc]);
DRM_WAKEUP(&dev->vbl_queue[crtc]);
+ drm_handle_vblank_events(dev, crtc);
}
EXPORT_SYMBOL(drm_handle_vblank);
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index 55bb8a8..adb864d 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -220,9 +220,11 @@
INIT_LIST_HEAD(&dev->ctxlist);
INIT_LIST_HEAD(&dev->vmalist);
INIT_LIST_HEAD(&dev->maplist);
+ INIT_LIST_HEAD(&dev->vblank_event_list);
spin_lock_init(&dev->count_lock);
spin_lock_init(&dev->drw_lock);
+ spin_lock_init(&dev->event_lock);
init_timer(&dev->timer);
mutex_init(&dev->struct_mutex);
mutex_init(&dev->ctxlist_mutex);
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 7f436ec..2fa2178 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -333,6 +333,7 @@
.mmap = drm_gem_mmap,
.poll = drm_poll,
.fasync = drm_fasync,
+ .read = drm_read,
#ifdef CONFIG_COMPAT
.compat_ioctl = i915_compat_ioctl,
#endif
