/* Subtract time delta from raw timestamp to get final
* vblank_time timestamp for end of vblank.
*/
- etime = ktime_sub_ns(etime, delta_ns);
+ if (delta_ns < 0)
+ etime = ktime_add_ns(etime, -delta_ns);
+ else
+ etime = ktime_sub_ns(etime, delta_ns);
*vblank_time = ktime_to_timeval(etime);
DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",