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>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index eeefb6369e19..fe52254df60c 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -426,6 +426,14 @@ struct drm_buf_entry {
         struct drm_freelist freelist;
 };
 
+/* Event queued up for userspace to read */
+struct drm_pending_event {
+        struct drm_event *event;
+        struct list_head link;
+        struct drm_file *file_priv;
+        void (*destroy)(struct drm_pending_event *event);
+};
+
 /** File private data */
 struct drm_file {
         int authenticated;
@@ -449,6 +457,10 @@ struct drm_file {
         struct drm_master *master; /* master this node is currently associated with
                                       N.B. not always minor->master */
         struct list_head fbs;
+
+        wait_queue_head_t event_wait;
+        struct list_head event_list;
+        int event_space;
 };
 
 /** Wait queue */
@@ -897,6 +909,12 @@ struct drm_minor {
         struct drm_mode_group mode_group;
 };
 
+struct drm_pending_vblank_event {
+        struct drm_pending_event base;
+        int pipe;
+        struct drm_event_vblank event;
+};
+
 /**
  * DRM device structure. This structure represent a complete card that
  * may contain multiple heads.
@@ -996,6 +1014,12 @@ struct drm_device {
 
         u32 max_vblank_count;           /**< size of vblank counter register */
 
+        /**
+         * List of events
+         */
+        struct list_head vblank_event_list;
+        spinlock_t event_lock;
+
         /*@} */
         cycles_t ctx_start;
         cycles_t lck_start;
@@ -1132,6 +1156,8 @@ extern int drm_lastclose(struct drm_device *dev);
 extern int drm_open(struct inode *inode, struct file *filp);
 extern int drm_stub_open(struct inode *inode, struct file *filp);
 extern int drm_fasync(int fd, struct file *filp, int on);
+extern ssize_t drm_read(struct file *filp, char __user *buffer,
+                        size_t count, loff_t *offset);
 extern int drm_release(struct inode *inode, struct file *filp);
 
                                 /* Mapping support (drm_vm.h) */