ktime_to_ns
if (ktime_to_ns(timeout) < 0)
timeout_jiffies = nsecs_to_jiffies(ktime_to_ns(timeout));
ktime_to_ns(ktime_sub(deadline, ktime_get())) > 0)
timeout_ns = ktime_to_ns(ktime_sub(abs_timeout, now));
diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
get_seq->sequence_ns = ktime_to_ns(now);
u64 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
e->event.seq.time_ns = ktime_to_ns(now);
args->timeout_ns -= ktime_to_ns(ktime_sub(ktime_get(), start));
period_ns = ktime_to_ns(ktime_sub(now, i915->pmu.timer_last));
val = ktime_to_ns(intel_engine_get_busy_time(engine));