handle missing pulses in ts2phc (RHEL-112344)

Resolves: RHEL-112344

linuxptp-ppsmiss.patch

@@ -0,0 +1,79 @@
+commit 5d735c810c8f9fd9916a3eb87398f5f9d6b1d278
+Author: Miroslav Lichvar <mlichvar@redhat.com>
+Date:   Thu Aug 28 15:14:01 2025 +0200
+
+    ts2phc: Better handle missing pulses with multiple sinks.
+    
+    The ts2phc_pps_sink_poll() function waits until it has collected pulses
+    for all active sinks, or a timeout of 2 seconds between events is
+    reached.
+    
+    If a sink missed a pulse (e.g. after a port state change and switching
+    PPS signal direction in the external PPS mode) and the next pulse of
+    that sink came before pulses of the other sinks, it was mixed with
+    events of the previous pulse and the measured offset had an error of
+    1/rate seconds.
+    
+    To avoid mixing events corresponding to different pulses, adjust the
+    poll() timeout so that it waits only up to a third of the pulse period
+    after the first received event.
+    
+    (Rebased to 4.4)
+    
+    Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
+    Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
+
+diff --git a/ts2phc_pps_sink.c b/ts2phc_pps_sink.c
+index 9076de9..72d8ea4 100644
+--- a/ts2phc_pps_sink.c
++++ b/ts2phc_pps_sink.c
+@@ -381,10 +381,11 @@ void ts2phc_pps_sink_cleanup(struct ts2phc_private *priv)
+ int ts2phc_pps_sink_poll(struct ts2phc_private *priv)
+ {
+ 	struct ts2phc_sink_array *polling_array = priv->polling_array;
++	bool first_poll = true, ignore_any = false;
+ 	bool all_sinks_have_events = false;
+-	bool ignore_any = false;
++	struct timespec first_ts = {0}, ts;
++	int cnt, timeout;
+ 	unsigned int i;
+-	int cnt;
+ 
+ 	for (i = 0; i < priv->n_sinks; i++)
+ 		polling_array->collected_events[i] = 0;
+@@ -395,7 +396,22 @@ int ts2phc_pps_sink_poll(struct ts2phc_private *priv)
+ 		if (!is_running())
+ 			return 0;
+ 
+-		cnt = poll(polling_array->pfd, priv->n_sinks, 2000);
++		/*
++		 * Collect only events within a third of the pulse period to
++		 * avoid mixing events corresponding to different pulses.
++		 */
++		if (first_poll) {
++			timeout = 2000;
++		} else {
++			clock_gettime(CLOCK_MONOTONIC, &ts);
++			timeout = 333;
++			timeout -= (ts.tv_sec - first_ts.tv_sec) * 1000 +
++				   (ts.tv_nsec - first_ts.tv_nsec) / 1000000;
++			if (timeout < 0)
++				timeout = 0;
++		}
++
++		cnt = poll(polling_array->pfd, priv->n_sinks, timeout);
+ 		if (cnt < 0) {
+ 			if (errno == EINTR) {
+ 				return 0;
+@@ -408,6 +424,11 @@ int ts2phc_pps_sink_poll(struct ts2phc_private *priv)
+ 			return 0;
+ 		}
+ 
++		if (first_poll) {
++			clock_gettime(CLOCK_MONOTONIC, &first_ts);
++			first_poll = false;
++		}
++
+ 		for (i = 0; i < priv->n_sinks; i++) {
+ 			if (polling_array->pfd[i].revents & POLLERR) {
+ 				sink = polling_array->sink[i];

linuxptp.spec

@@ -43,6 +43,8 @@ Patch9:		linuxptp-externalgm.patch
 Patch10:	linuxptp-rtnlinit.patch
 # fix unicast server to recover after port fault
 Patch11:	linuxptp-unirecover.patch
+# handle missing pulses in ts2phc
+Patch13:	linuxptp-ppsmiss.patch
 
 BuildRequires:	gcc gcc-c++ gnutls-devel make systemd