+/*
+ * Request a page flip on the specified crtc.
+ *
+ * This ioctl will ask KMS to schedule a page flip for the specified
+ * crtc. Once any pending rendering targeting the specified fb (as of
+ * ioctl time) has completed, the crtc will be reprogrammed to display
+ * that fb after the next vertical refresh. The ioctl returns
+ * immediately, but subsequent rendering to the current fb will block
+ * in the execbuffer ioctl until the page flip happens. If a page
+ * flip is already pending as the ioctl is called, EBUSY will be
+ * returned.
+ *
+ * The ioctl supports one flag, DRM_MODE_PAGE_FLIP_EVENT, which will
+ * request that drm sends back a vblank event (see drm.h: struct
+ * drm_event_vblank) when the page flip is done. The user_data field
+ * passed in with this ioctl will be returned as the user_data field
+ * in the vblank event struct.
+ *
+ * The reserved field must be zero until we figure out something
+ * clever to use it for.
+ */
+