diff --git a/clock.c b/clock.c
index 199c0cb..cf087e8 100644
--- a/clock.c
+++ b/clock.c
@@ -1767,11 +1767,9 @@ enum clock_type clock_type(struct clock *c)
 	return c->type;
 }
 
-void clock_check_ts(struct clock *c, struct timespec ts)
+void clock_check_ts(struct clock *c, uint64_t ts)
 {
-	if (c->sanity_check &&
-	    clockcheck_sample(c->sanity_check,
-			      ts.tv_sec * NS_PER_SEC + ts.tv_nsec)) {
+	if (c->sanity_check && clockcheck_sample(c->sanity_check, ts)) {
 		servo_reset(c->servo);
 	}
 }
diff --git a/clock.h b/clock.h
index 94d4ad0..3fa026d 100644
--- a/clock.h
+++ b/clock.h
@@ -316,7 +316,7 @@ enum clock_type clock_type(struct clock *c);
  * @param c  The clock instance.
  * @param ts The time stamp.
  */
-void clock_check_ts(struct clock *c, struct timespec ts);
+void clock_check_ts(struct clock *c, uint64_t ts);
 
 /**
  * Obtain ratio between master's frequency and current clock frequency.
diff --git a/port.c b/port.c
index 25507e2..d1c95ab 100644
--- a/port.c
+++ b/port.c
@@ -2519,7 +2519,8 @@ enum fsm_event port_event(struct port *p, int fd_index)
 	}
 	if (msg_sots_valid(msg)) {
 		ts_add(&msg->hwts.ts, -p->rx_timestamp_offset);
-		clock_check_ts(p->clock, msg->hwts.ts);
+		clock_check_ts(p->clock,
+			       tmv_to_nanoseconds(timespec_to_tmv(msg->hwts.ts)));
 	}
 	if (port_ignore(p, msg)) {
 		msg_put(msg);