Detect change to new foreign master only if already synchronized to a foreign master

Do it only if a foreign master is changed to a new one, do not do it if this is the first foreign master, i.e. we were not synchronized to any PTP master and the clockIdentity in the parent DS was our own. In other words, the flag newGrandmaster is meant to detect change between foreign masters, and not connection to a foreign master when before there was none). The "if" was added to prevent unnecessary trashing between SLAVE and UNCALIBRATED state (without the if, the UNCALIBRATED would be forced unnecesserily when connecting the link).

Detect change to new foreign master only if already synchronized to a foreign master
Do it only if a foreign master is changed to a new one, do not do it if this is the first foreign master, i.e. we were not synchronized to any PTP master and the clockIdentity in the parent DS was our own. In other words, the flag newGrandmaster is meant to detect change between foreign masters, and not connection to a foreign master when before there was none). The "if" was added to prevent unnecessary trashing between SLAVE and UNCALIBRATED state (without the if, the UNCALIBRATED would be forced unnecesserily when connecting the link).
bd2f31ab · Maciej Lipinski · 7d72d594 · bd2f31ab
Commit bd2f31ab authored Jun 10, 2020 by Maciej Lipinski
Hide whitespace changes
Inline Side-by-side

Showing with 16 additions and 1 deletion

bmc.c proto-standard/bmc.c +16 -1

No files found.
--- a/proto-standard/bmc.c
+++ b/proto-standard/bmc.c
@@ -130,6 +130,7 @@ void bmc_s1(struct pp_instance *ppi,
 {
 	parentDS_t *parent = DSPAR(ppi);
 	timePropertiesDS_t *prop = DSPRO(ppi);
+        defaultDS_t *defds = DSDEF(ppi);
 	int ret = 0;
 	int offset, leap59, leap61;
 	int hours, minutes, seconds;
@@ -140,8 +141,22 @@ void bmc_s1(struct pp_instance *ppi,
 	/* Check if it is a new foreign master
 	 * In this case the BMCA state machine must be informed
 	 * to transition form SLAVE to UNCALIBRATED state.
+	 * Do it only if a foreign master is changed to a new one,
+	 * do not do it if this is the first foreign master, i.e.
+         * we were not synchronized to any PTP master and the clockIdentity
+         * in the parent DS was our own. In other words, the flag
+         * newGrandmaster is meant to detect change between foreign
+         * masters, and not connection to a foreign master when
+         * before there was none). The "if" was added to prevent
+         * unnecessary trashing between SLAVE and UNCALIBRATED
+         * state (without the if, the UNCALIBRATED would be forced
+         * unnecesserily when connecting the link).
+         * FIXME: change the name from newGrandmaster to newForeignMaster
 	 */
-	parent->newGrandmaster=bmc_pidcmp(&parent->parentPortIdentity,&frgn_master->sourcePortIdentity)!=0;
+	if ( bmc_idcmp(&defds->clockIdentity, &parent->parentPortIdentity.clockIdentity) != 0)
+		parent->newGrandmaster=bmc_pidcmp(&parent->parentPortIdentity,&frgn_master->sourcePortIdentity)!=0;
+	else
+		parent->newGrandmaster= FALSE;

 	/* Parent DS */
 	parent->parentPortIdentity = frgn_master->sourcePortIdentity;