servo: when setting time, make no calculations

When offset from master is more than one second, the code used to time->get, subtract and then time->set. However, in white rabbit we cannot get the WR time and time->get returns the unix time instead. The only way to have hardware time is timestamping a frame. Thus, use the master's "T4" that we just received plus the one-way-delay as an approximation of the current hardware time. Later T1..T4 tuples will complete the fine synchronization. Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

servo: when setting time, make no calculations
When offset from master is more than one second, the code used to time->get, subtract and then time->set. However, in white rabbit we cannot get the WR time and time->get returns the unix time instead. The only way to have hardware time is timestamping a frame. Thus, use the master's "T4" that we just received plus the one-way-delay as an approximation of the current hardware time. Later T1..T4 tuples will complete the fine synchronization. Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
ec537cd1 · Alessandro Rubini · 8146c5e4 · ec537cd1
Commit ec537cd1 authored Sep 19, 2013 by Alessandro Rubini
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servo.c proto-standard/servo.c +4 -3

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--- a/proto-standard/servo.c
+++ b/proto-standard/servo.c
@@ -206,9 +206,10 @@ void pp_servo_got_resp(struct pp_instance *ppi)
 		/* if secs, reset clock or set freq adjustment to max */
 		if (!OPTS(ppi)->no_adjust) {
 			if (!OPTS(ppi)->no_rst_clk) {
-				/* FIXME: use adjust instead of set? */
-				ppi->t_ops->get(ppi, &time_tmp);
-				sub_TimeInternal(&time_tmp, &time_tmp, ofm);
+				/* Can't use "adjust, limited to +/- 2s */
+				time_tmp = ppi->t4;
+				add_TimeInternal(&time_tmp, &time_tmp,
+						 &DSCUR(ppi)->oneWayDelay);
 				ppi->t_ops->set(ppi, &time_tmp);
 				pp_servo_init(ppi);
 			} else {