@@ -131,12 +131,11 @@ static void drm_update_vblank_count(struct drm_device *dev, int crtc)
/* Reinitialize corresponding vblank timestamp if high-precision query
* available. Skip this step if query unsupported or failed. Will
- * reinitialize delayed at next vblank interrupt in that case.
+ * reinitialize delayed at next vblank interrupt in that case and
+ * assign 0 for now, to mark the vblanktimestamp as invalid.
*/
- if (rc) {
- tslot = atomic_read(&vblank->count) + diff;
- vblanktimestamp(dev, crtc, tslot) = t_vblank;
- }
+ tslot = atomic_read(&vblank->count) + diff;
+ vblanktimestamp(dev, crtc, tslot) = rc ? t_vblank : (struct timeval) {0, 0};
smp_mb__before_atomic();
atomic_add(diff, &vblank->count);