drm_send_vblank_event — helper to send vblank event after pageflip
| void drm_send_vblank_event ( | struct drm_device * dev, | 
| unsigned int pipe, | |
| struct drm_pending_vblank_event * e ); | 
Updates sequence # and timestamp on event, and sends it to userspace. Caller must hold event lock.
   This is the legacy version of drm_crtc_send_vblank_event.