Before DPMS off driver disables vblank.
It should be balanced by vblank enable after DPMS on.
The patch fixes issue with page_flip ioctl not being able
to acquire vblank counter introduced by patch:
drm: Always reject drm_vblank_get() after drm_vblank_off()
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
                                !atomic_read(&exynos_crtc->pending_flip),
                                HZ/20))
                        atomic_set(&exynos_crtc->pending_flip, 0);
-               drm_vblank_off(crtc->dev, exynos_crtc->pipe);
+               drm_crtc_vblank_off(crtc);
        }
 
        if (manager->ops->dpms)
                manager->ops->dpms(manager, mode);
 
        exynos_crtc->dpms = mode;
+
+       if (mode == DRM_MODE_DPMS_ON)
+               drm_crtc_vblank_on(crtc);
 }
 
 static void exynos_drm_crtc_prepare(struct drm_crtc *crtc)