diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 2e8c27d48f2b..6b38a6b43ce8 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1022,7 +1022,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
 		spin_unlock(&c3_lock);
 	}
 	kt2 = ktime_get_real();
-	idle_time_ns = ktime_to_us(ktime_sub(kt2, kt1));
+	idle_time_ns = ktime_to_ns(ktime_sub(kt2, kt1));
 	idle_time = idle_time_ns;
 	do_div(idle_time, NSEC_PER_USEC);