Make Await SyncTrigger functions generic

Update all the functions dealing with Await
sync triggers handle generic sync objects
instead of just counters.  This will
facilitate code sharing between the counter
sync waits and the fence sync waits.

Signed-off-by: James Jones <jajones@nvidia.com>
Reviewed-by: Keith Packard <keithp@keithp.com>

2 files changed, 200 insertions, 114 deletions

diff --git a/Xext/sync.c b/Xext/sync.c
index d5187dd21..29449037a 100644
--- a/Xext/sync.c
+++ b/Xext/sync.c
@@ -107,18 +107,19 @@ static void SyncInitIdleTime(void);
  *  delete and add triggers on this list.
  */
 static void
-SyncDeleteTriggerFromCounter(SyncTrigger *pTrigger)
+SyncDeleteTriggerFromSyncObject(SyncTrigger *pTrigger)
 {
     SyncTriggerList *pCur;
     SyncTriggerList *pPrev;
+    SyncCounter *pCounter;
 
-    /* pCounter needs to be stored in pTrigger before calling here. */
+    /* pSync needs to be stored in pTrigger before calling here. */
 
-    if (!pTrigger->pCounter)
+    if (!pTrigger->pSync)
 	return;
 
     pPrev = NULL;
-    pCur = pTrigger->pCounter->sync.pTriglist;
+    pCur = pTrigger->pSync->pTriglist;
 
     while (pCur)
     {
@@ -127,7 +128,7 @@ SyncDeleteTriggerFromCounter(SyncTrigger *pTrigger)
 	    if (pPrev)
 		pPrev->next = pCur->next;
 	    else
-		pTrigger->pCounter->sync.pTriglist = pCur->next;
+		pTrigger->pSync->pTriglist = pCur->next;
 
 	    free(pCur);
 	    break;
@@ -137,21 +138,27 @@ SyncDeleteTriggerFromCounter(SyncTrigger *pTrigger)
 	pCur = pCur->next;
     }
 
-    if (IsSystemCounter(pTrigger->pCounter))
-	SyncComputeBracketValues(pTrigger->pCounter);
+    if (SYNC_COUNTER == pTrigger->pSync->type)
+    {
+	pCounter = (SyncCounter *)pTrigger->pSync;
+
+	if (IsSystemCounter(pCounter))
+	    SyncComputeBracketValues(pCounter);
+    }
 }
 
 
 static int
-SyncAddTriggerToCounter(SyncTrigger *pTrigger)
+SyncAddTriggerToSyncObject(SyncTrigger *pTrigger)
 {
     SyncTriggerList *pCur;
+    SyncCounter *pCounter;
 
-    if (!pTrigger->pCounter)
+    if (!pTrigger->pSync)
 	return Success;
 
     /* don't do anything if it's already there */
-    for (pCur = pTrigger->pCounter->sync.pTriglist; pCur; pCur = pCur->next)
+    for (pCur = pTrigger->pSync->pTriglist; pCur; pCur = pCur->next)
     {
 	if (pCur->pTrigger == pTrigger)
 	    return Success;
@@ -161,11 +168,16 @@ SyncAddTriggerToCounter(SyncTrigger *pTrigger)
 	return BadAlloc;
 
     pCur->pTrigger = pTrigger;
-    pCur->next = pTrigger->pCounter->sync.pTriglist;
-    pTrigger->pCounter->sync.pTriglist = pCur;
+    pCur->next = pTrigger->pSync->pTriglist;
+    pTrigger->pSync->pTriglist = pCur;
 
-    if (IsSystemCounter(pTrigger->pCounter))
-	SyncComputeBracketValues(pTrigger->pCounter);
+    if (SYNC_COUNTER == pTrigger->pSync->type)
+    {
+	pCounter = (SyncCounter *)pTrigger->pSync;
+
+	if (IsSystemCounter(pCounter))
+	    SyncComputeBracketValues(pCounter);
+    }
 
     return Success;
 }
@@ -188,69 +200,91 @@ SyncAddTriggerToCounter(SyncTrigger *pTrigger)
 static Bool
 SyncCheckTriggerPositiveComparison(SyncTrigger *pTrigger, CARD64 oldval)
 {
-    return (pTrigger->pCounter == NULL ||
-	    XSyncValueGreaterOrEqual(pTrigger->pCounter->value,
-				     pTrigger->test_value));
+    SyncCounter *pCounter;
+
+    assert(!pTrigger->pSync || (SYNC_COUNTER == pTrigger->pSync->type));
+    pCounter = (SyncCounter *)pTrigger->pSync;
+
+    return (pCounter == NULL ||
+	    XSyncValueGreaterOrEqual(pCounter->value, pTrigger->test_value));
 }
 
 static Bool
 SyncCheckTriggerNegativeComparison(SyncTrigger *pTrigger,  CARD64 oldval)
 {
-    return (pTrigger->pCounter == NULL ||
-	    XSyncValueLessOrEqual(pTrigger->pCounter->value,
-				  pTrigger->test_value));
+    SyncCounter *pCounter;
+
+    assert(!pTrigger->pSync || (SYNC_COUNTER == pTrigger->pSync->type));
+    pCounter = (SyncCounter *)pTrigger->pSync;
+
+    return (pCounter == NULL ||
+	    XSyncValueLessOrEqual(pCounter->value, pTrigger->test_value));
 }
 
 static Bool
 SyncCheckTriggerPositiveTransition(SyncTrigger *pTrigger, CARD64 oldval)
 {
-    return (pTrigger->pCounter == NULL ||
+    SyncCounter *pCounter;
+
+    assert(!pTrigger->pSync || (SYNC_COUNTER == pTrigger->pSync->type));
+    pCounter = (SyncCounter *)pTrigger->pSync;
+
+    return (pCounter == NULL ||
 	    (XSyncValueLessThan(oldval, pTrigger->test_value) &&
-	     XSyncValueGreaterOrEqual(pTrigger->pCounter->value,
-				      pTrigger->test_value)));
+	     XSyncValueGreaterOrEqual(pCounter->value, pTrigger->test_value)));
 }
 
 static Bool
 SyncCheckTriggerNegativeTransition(SyncTrigger *pTrigger, CARD64 oldval)
 {
-    return (pTrigger->pCounter == NULL ||
+    SyncCounter *pCounter;
+
+    assert(!pTrigger->pSync || (SYNC_COUNTER == pTrigger->pSync->type));
+    pCounter = (SyncCounter *)pTrigger->pSync;
+
+    return (pCounter == NULL ||
 	    (XSyncValueGreaterThan(oldval, pTrigger->test_value) &&
-	     XSyncValueLessOrEqual(pTrigger->pCounter->value,
-				   pTrigger->test_value)));
+	     XSyncValueLessOrEqual(pCounter->value, pTrigger->test_value)));
 }
 
 static int
-SyncInitTrigger(ClientPtr client, SyncTrigger *pTrigger, XSyncCounter counter,
-		Mask changes)
+SyncInitTrigger(ClientPtr client, SyncTrigger *pTrigger, XID syncObject,
+		RESTYPE resType, Mask changes)
 {
-    SyncCounter *pCounter = pTrigger->pCounter;
+    SyncObject *pSync = pTrigger->pSync;
+    SyncCounter *pCounter = NULL;
     int		rc;
-    Bool	newcounter = FALSE;
+    Bool	newSyncObject = FALSE;
 
     if (changes & XSyncCACounter)
     {
-	if (counter == None)
-	    pCounter = NULL;
-	else if (Success != (rc = dixLookupResourceByType ((pointer *)&pCounter,
-				counter, RTCounter, client, DixReadAccess)))
+	if (syncObject == None)
+	    pSync = NULL;
+	else if (Success != (rc = dixLookupResourceByType ((pointer *)&pSync,
+				syncObject, resType, client, DixReadAccess)))
 	{
-	    client->errorValue = counter;
+	    client->errorValue = syncObject;
 	    return rc;
 	}
-	if (pCounter != pTrigger->pCounter)
+	if (pSync != pTrigger->pSync)
 	{ /* new counter for trigger */
-	    SyncDeleteTriggerFromCounter(pTrigger);
-	    pTrigger->pCounter = pCounter;
-	    newcounter = TRUE;
+	    SyncDeleteTriggerFromSyncObject(pTrigger);
+	    pTrigger->pSync = pSync;
+	    newSyncObject = TRUE;
 	}
     }
 
     /* if system counter, ask it what the current value is */
 
-    if (IsSystemCounter(pCounter))
+    if (SYNC_COUNTER == pSync->type)
     {
-	(*pCounter->pSysCounterInfo->QueryValue) ((pointer) pCounter,
-						  &pCounter->value);
+	pCounter = (SyncCounter *)pSync;
+
+	if (IsSystemCounter(pCounter))
+	{
+	    (*pCounter->pSysCounterInfo->QueryValue) ((pointer) pCounter,
+						      &pCounter->value);
+	}
     }
 
     if (changes & XSyncCAValueType)
@@ -277,16 +311,16 @@ SyncInitTrigger(ClientPtr client, SyncTrigger *pTrigger, XSyncCounter counter,
 
 	switch (pTrigger->test_type)
 	{
-        case XSyncPositiveTransition:
+	case XSyncPositiveTransition:
 	    pTrigger->CheckTrigger = SyncCheckTriggerPositiveTransition;
 	    break;
-        case XSyncNegativeTransition:
+	case XSyncNegativeTransition:
 	    pTrigger->CheckTrigger = SyncCheckTriggerNegativeTransition;
 	    break;
-        case XSyncPositiveComparison:
+	case XSyncPositiveComparison:
 	    pTrigger->CheckTrigger = SyncCheckTriggerPositiveComparison;
 	    break;
-        case XSyncNegativeComparison:
+	case XSyncNegativeComparison:
 	    pTrigger->CheckTrigger = SyncCheckTriggerNegativeComparison;
 	    break;
 	}
@@ -315,12 +349,12 @@ SyncInitTrigger(ClientPtr client, SyncTrigger *pTrigger, XSyncCounter counter,
     /*  we wait until we're sure there are no errors before registering
      *  a new counter on a trigger
      */
-    if (newcounter)
+    if (newSyncObject)
     {
-	if ((rc = SyncAddTriggerToCounter(pTrigger)) != Success)
+	if ((rc = SyncAddTriggerToSyncObject(pTrigger)) != Success)
 	    return rc;
     }
-    else if (IsSystemCounter(pCounter))
+    else if (pCounter && IsSystemCounter(pCounter))
     {
 	SyncComputeBracketValues(pCounter);
     }
@@ -338,16 +372,21 @@ SyncSendAlarmNotifyEvents(SyncAlarm *pAlarm)
     SyncAlarmClientList *pcl;
     xSyncAlarmNotifyEvent ane;
     SyncTrigger *pTrigger = &pAlarm->trigger;
+    SyncCounter *pCounter;
+
+    assert(!pTrigger->pSync || (SYNC_COUNTER == pTrigger->pSync->type));
+
+    pCounter = (SyncCounter *)pTrigger->pSync;
 
     UpdateCurrentTime();
 
     ane.type = SyncEventBase + XSyncAlarmNotify;
     ane.kind = XSyncAlarmNotify;
     ane.alarm = pAlarm->alarm_id;
-    if (pTrigger->pCounter)
+    if (pTrigger->pSync && SYNC_COUNTER == pTrigger->pSync->type)
     {
-	ane.counter_value_hi = XSyncValueHigh32(pTrigger->pCounter->value);
-	ane.counter_value_lo = XSyncValueLow32(pTrigger->pCounter->value);
+	ane.counter_value_hi = XSyncValueHigh32(pCounter->value);
+	ane.counter_value_lo = XSyncValueLow32(pCounter->value);
     }
     else
     { /* XXX what else can we do if there's no counter? */
@@ -390,14 +429,25 @@ SyncSendCounterNotifyEvents(ClientPtr client, SyncAwait **ppAwait,
 	SyncTrigger *pTrigger = &(*ppAwait)->trigger;
 	pev->type = SyncEventBase + XSyncCounterNotify;
 	pev->kind = XSyncCounterNotify;
-	pev->counter = pTrigger->pCounter->sync.id;
+	pev->counter = pTrigger->pSync->id;
 	pev->wait_value_lo = XSyncValueLow32(pTrigger->test_value);
 	pev->wait_value_hi = XSyncValueHigh32(pTrigger->test_value);
-	pev->counter_value_lo = XSyncValueLow32(pTrigger->pCounter->value);
-	pev->counter_value_hi = XSyncValueHigh32(pTrigger->pCounter->value);
+	if (SYNC_COUNTER == pTrigger->pSync->type)
+	{
+	    SyncCounter *pCounter = (SyncCounter *)pTrigger->pSync;
+
+	    pev->counter_value_lo = XSyncValueLow32(pCounter->value);
+	    pev->counter_value_hi = XSyncValueHigh32(pCounter->value);
+	}
+	else
+	{
+	    pev->counter_value_lo = 0;
+	    pev->counter_value_hi = 0;
+	}
+
 	pev->time = currentTime.milliseconds;
 	pev->count = num_events - i - 1; /* events remaining */
-	pev->destroyed = pTrigger->pCounter->sync.beingDestroyed;
+	pev->destroyed = pTrigger->pSync->beingDestroyed;
     }
     /* swapping will be taken care of by this */
     WriteEventsToClient(client, num_events, (xEvent *)pEvents);
@@ -415,7 +465,7 @@ SyncAlarmCounterDestroyed(SyncTrigger *pTrigger)
 
     pAlarm->state = XSyncAlarmInactive;
     SyncSendAlarmNotifyEvents(pAlarm);
-    pTrigger->pCounter = NULL;
+    pTrigger->pSync = NULL;
 }
 
 
@@ -426,8 +476,12 @@ static void
 SyncAlarmTriggerFired(SyncTrigger *pTrigger)
 {
     SyncAlarm *pAlarm = (SyncAlarm *)pTrigger;
+    SyncCounter *pCounter;
     CARD64 new_test_value;
 
+    assert(!pTrigger->pSync || (SYNC_COUNTER == pTrigger->pSync->type));
+    pCounter = (SyncCounter *)pTrigger->pSync;
+
     /* no need to check alarm unless it's active */
     if (pAlarm->state != XSyncAlarmActive)
 	return;
@@ -437,7 +491,7 @@ SyncAlarmTriggerFired(SyncTrigger *pTrigger)
      *    no change is made to value (test-value) and the alarm
      *    state is changed to Inactive before the event is generated."
      */
-    if (pAlarm->trigger.pCounter == NULL
+    if (pCounter == NULL
 	|| (XSyncValueIsZero(pAlarm->delta)
 	    && (pAlarm->trigger.test_type == XSyncPositiveComparison
 		|| pAlarm->trigger.test_type == XSyncNegativeComparison)))
@@ -450,6 +504,10 @@ SyncAlarmTriggerFired(SyncTrigger *pTrigger)
 	Bool overflow;
 	CARD64 oldvalue;
 	SyncTrigger *paTrigger = &pAlarm->trigger;
+	SyncCounter *paCounter;
+
+	assert(!paTrigger->pSync || (SYNC_COUNTER == paTrigger->pSync->type));
+	paCounter = (SyncCounter *)pTrigger->pSync;
 
 	/* "The alarm is updated by repeatedly adding delta to the
 	 *  value of the trigger and re-initializing it until it
@@ -465,7 +523,7 @@ SyncAlarmTriggerFired(SyncTrigger *pTrigger)
 			  pAlarm->delta, &overflow);
 	} while (!overflow &&
 	      (*paTrigger->CheckTrigger)(paTrigger,
-					paTrigger->pCounter->value));
+					paCounter->value));
 
 	new_test_value = paTrigger->test_value;
 	paTrigger->test_value = oldvalue;
@@ -532,46 +590,51 @@ SyncAwaitTriggerFired(SyncTrigger *pTrigger)
 	 *  always generated if the counter for one of the triggers is
 	 *  destroyed."
 	 */
-	if (pAwait->trigger.pCounter->sync.beingDestroyed)
+	if (pAwait->trigger.pSync->beingDestroyed)
 	{
 	    ppAwait[num_events++] = pAwait;
 	    continue;
 	}
+	
+	if (SYNC_COUNTER == pAwait->trigger.pSync->type)
+	{
+	    SyncCounter *pCounter = (SyncCounter *) pAwait->trigger.pSync;
 
-	/* "The difference between the counter and the test value is
-	 *  calculated by subtracting the test value from the value of
-	 *  the counter."
-	 */
-	XSyncValueSubtract(&diff, pAwait->trigger.pCounter->value,
-			   pAwait->trigger.test_value, &overflow);
+	    /* "The difference between the counter and the test value is
+	     *  calculated by subtracting the test value from the value of
+	     *  the counter."
+	     */
+	    XSyncValueSubtract(&diff, pCounter->value,
+			       pAwait->trigger.test_value, &overflow);
 
-	/* "If the difference lies outside the range for an INT64, an
-	 *  event is not generated."
-	 */
-	if (overflow)
-	    continue;
-	diffgreater = XSyncValueGreaterThan(diff, pAwait->event_threshold);
-	diffequal   = XSyncValueEqual(diff, pAwait->event_threshold);
-
-	/* "If the test-type is PositiveTransition or
-	 *  PositiveComparison, a CounterNotify event is generated if
-	 *  the difference is at least event-threshold. If the test-type
-	 *  is NegativeTransition or NegativeComparison, a CounterNotify
-	 *  event is generated if the difference is at most
-	 *  event-threshold."
-	 */
+	    /* "If the difference lies outside the range for an INT64, an
+	     *  event is not generated."
+	     */
+	    if (overflow)
+		continue;
+	    diffgreater = XSyncValueGreaterThan(diff, pAwait->event_threshold);
+	    diffequal   = XSyncValueEqual(diff, pAwait->event_threshold);
+
+	    /* "If the test-type is PositiveTransition or
+	     *  PositiveComparison, a CounterNotify event is generated if
+	     *  the difference is at least event-threshold. If the test-type
+	     *  is NegativeTransition or NegativeComparison, a CounterNotify
+	     *  event is generated if the difference is at most
+	     *  event-threshold."
+	     */
 
-	if ( ((pAwait->trigger.test_type == XSyncPositiveComparison ||
-	       pAwait->trigger.test_type == XSyncPositiveTransition)
-	       && (diffgreater || diffequal))
-	     ||
-	     ((pAwait->trigger.test_type == XSyncNegativeComparison ||
-	       pAwait->trigger.test_type == XSyncNegativeTransition)
-	      && (!diffgreater) /* less or equal */
-	      )
-	   )
-	{
-	    ppAwait[num_events++] = pAwait;
+	    if ( ((pAwait->trigger.test_type == XSyncPositiveComparison ||
+		   pAwait->trigger.test_type == XSyncPositiveTransition)
+		  && (diffgreater || diffequal))
+		 ||
+		 ((pAwait->trigger.test_type == XSyncNegativeComparison ||
+		   pAwait->trigger.test_type == XSyncNegativeTransition)
+		  && (!diffgreater) /* less or equal */
+		 )
+	       )
+	    {
+		ppAwait[num_events++] = pAwait;
+	    }
 	}
     }
     if (num_events)
@@ -693,7 +756,7 @@ SyncChangeAlarmAttributes(ClientPtr client, SyncAlarm *pAlarm, Mask mask,
     Mask	   origmask = mask;
 
     counter =
-	pAlarm->trigger.pCounter ? pAlarm->trigger.pCounter->sync.id : None;
+	pAlarm->trigger.pSync ? pAlarm->trigger.pSync->id : None;
 
     while (mask)
     {
@@ -773,7 +836,7 @@ SyncChangeAlarmAttributes(ClientPtr client, SyncAlarm *pAlarm, Mask mask,
     }
 
     /* postpone this until now, when we're sure nothing else can go wrong */
-    if ((status = SyncInitTrigger(client, &pAlarm->trigger, counter,
+    if ((status = SyncInitTrigger(client, &pAlarm->trigger, counter, RTCounter,
 			     origmask & XSyncCAAllTrigger)) != Success)
 	return status;
 
@@ -996,7 +1059,7 @@ FreeAlarm(void *addr, XID id)
     while (pAlarm->pEventClients)
 	FreeResource(pAlarm->pEventClients->delete_id, RT_NONE);
 
-    SyncDeleteTriggerFromCounter(&pAlarm->trigger);
+    SyncDeleteTriggerFromSyncObject(&pAlarm->trigger);
 
     free(pAlarm);
     return Success;
@@ -1074,9 +1137,9 @@ FreeAwait(void *addr, XID id)
 	/* If the counter is being destroyed, FreeCounter will delete
 	 * the trigger list itself, so don't do it here.
 	 */
-	SyncCounter *pCounter = pAwait->trigger.pCounter;
-	if (pCounter && !pCounter->sync.beingDestroyed)
-	    SyncDeleteTriggerFromCounter(&pAwait->trigger);
+	SyncObject *pSync = pAwait->trigger.pSync;
+	if (pSync && !pSync->beingDestroyed)
+	    SyncDeleteTriggerFromSyncObject(&pAwait->trigger);
     }
     free(pAwaitUnion);
     return Success;
@@ -1462,7 +1525,7 @@ ProcSyncAwait(ClientPtr client)
 	if (pProtocolWaitConds->counter == None) /* XXX protocol change */
 	{
 	    /*  this should take care of removing any triggers created by
-	     *  this request that have already been registered on counters
+	     *  this request that have already been registered on sync objects
 	     */
 	    FreeResource(pAwaitUnion->header.delete_id, RT_NONE);
 	    client->errorValue = pProtocolWaitConds->counter;
@@ -1470,7 +1533,7 @@ ProcSyncAwait(ClientPtr client)
 	}
 
 	/* sanity checks are in SyncInitTrigger */
-	pAwait->trigger.pCounter = NULL;
+	pAwait->trigger.pSync = NULL;
 	pAwait->trigger.value_type = pProtocolWaitConds->value_type;
 	XSyncIntsToValue(&pAwait->trigger.wait_value,
 			 pProtocolWaitConds->wait_value_lo,
@@ -1478,11 +1541,12 @@ ProcSyncAwait(ClientPtr client)
 	pAwait->trigger.test_type = pProtocolWaitConds->test_type;
 
 	status = SyncInitTrigger(client, &pAwait->trigger,
-			 pProtocolWaitConds->counter, XSyncCAAllTrigger);
+				 pProtocolWaitConds->counter, RTCounter,
+				 XSyncCAAllTrigger);
 	if (status != Success)
 	{
 	    /*  this should take care of removing any triggers created by
-	     *  this request that have already been registered on counters
+	     *  this request that have already been registered on sync objects
 	     */
 	    FreeResource(pAwaitUnion->header.delete_id, RT_NONE);
 	    return status;
@@ -1504,11 +1568,20 @@ ProcSyncAwait(ClientPtr client)
     pAwait = &(pAwaitUnion+1)->await; /* skip over header */
     for (i = 0; i < items; i++, pAwait++)
     {
+	CARD64 value;
+
 	/*  don't have to worry about NULL counters because the request
 	 *  errors before we get here out if they occur
 	 */
-	if ((*pAwait->trigger.CheckTrigger)(&pAwait->trigger,
-					    pAwait->trigger.pCounter->value))
+	switch (pAwait->trigger.pSync->type) {
+	case SYNC_COUNTER:
+	    value = ((SyncCounter *)pAwait->trigger.pSync)->value;
+	    break;
+	default:
+	    XSyncIntToValue(&value, 0);
+	}
+
+	if ((*pAwait->trigger.CheckTrigger)(&pAwait->trigger, value))
 	{
 	    (*pAwait->trigger.TriggerFired)(&pAwait->trigger);
 	    break; /* once is enough */
@@ -1593,13 +1666,14 @@ ProcSyncCreateAlarm(ClientPtr client)
     /* set up defaults */
 
     pTrigger = &pAlarm->trigger;
-    pTrigger->pCounter = NULL;
+    pTrigger->pSync = NULL;
     pTrigger->value_type = XSyncAbsolute;
     XSyncIntToValue(&pTrigger->wait_value, 0L);
     pTrigger->test_type = XSyncPositiveComparison;
     pTrigger->TriggerFired = SyncAlarmTriggerFired;
     pTrigger->CounterDestroyed = SyncAlarmCounterDestroyed;
-    status = SyncInitTrigger(client, pTrigger, None, XSyncCAAllTrigger);
+    status = SyncInitTrigger(client, pTrigger, None, RTCounter,
+			     XSyncCAAllTrigger);
     if (status != Success)
     {
 	free(pAlarm);
@@ -1630,13 +1704,19 @@ ProcSyncCreateAlarm(ClientPtr client)
      *  in CreateAlarm and sets alarm state to Inactive.
      */
 
-    if (!pTrigger->pCounter)
+    if (!pTrigger->pSync)
     {
 	pAlarm->state = XSyncAlarmInactive; /* XXX protocol change */
     }
-    else if ((*pTrigger->CheckTrigger)(pTrigger, pTrigger->pCounter->value))
+    else
     {
-	(*pTrigger->TriggerFired)(pTrigger);
+	SyncCounter *pCounter;
+
+	assert(SYNC_COUNTER == pTrigger->pSync->type);
+	pCounter = (SyncCounter *)pTrigger->pSync;
+
+	if ((*pTrigger->CheckTrigger)(pTrigger, pCounter->value))
+	    (*pTrigger->TriggerFired)(pTrigger);
     }
 
     return Success;
@@ -1650,6 +1730,7 @@ ProcSyncChangeAlarm(ClientPtr client)
 {
     REQUEST(xSyncChangeAlarmReq);
     SyncAlarm   *pAlarm;
+    SyncCounter *pCounter = NULL;
     long        vmask;
     int         len, status;
 
@@ -1670,13 +1751,18 @@ ProcSyncChangeAlarm(ClientPtr client)
 					    (CARD32 *)&stuff[1])) != Success)
 	return status;
 
+    if (pAlarm->trigger.pSync)
+    {
+	assert(SYNC_COUNTER == pAlarm->trigger.pSync->type);
+	pCounter = (SyncCounter *)pAlarm->trigger.pSync;
+    }
+
     /*  see if alarm already triggered.  NULL counter WILL trigger
      *  in ChangeAlarm.
      */
 
-    if (!pAlarm->trigger.pCounter ||
-	(*pAlarm->trigger.CheckTrigger)(&pAlarm->trigger,
-					pAlarm->trigger.pCounter->value))
+    if (!pCounter ||
+	(*pAlarm->trigger.CheckTrigger)(&pAlarm->trigger, pCounter->value))
     {
 	(*pAlarm->trigger.TriggerFired)(&pAlarm->trigger);
     }
@@ -1704,7 +1790,7 @@ ProcSyncQueryAlarm(ClientPtr client)
     rep.sequenceNumber = client->sequence;
 
     pTrigger = &pAlarm->trigger;
-    rep.counter = (pTrigger->pCounter) ? pTrigger->pCounter->sync.id : None;
+    rep.counter = (pTrigger->pSync) ? pTrigger->pSync->id : None;
 
 #if 0 /* XXX unclear what to do, depends on whether relative value-types
        * are "consumed" immediately and are considered absolute from then
diff --git a/Xext/syncsrv.h b/Xext/syncsrv.h
index dafbfdf90..64e42cddb 100644
--- a/Xext/syncsrv.h
+++ b/Xext/syncsrv.h
@@ -101,7 +101,7 @@ typedef struct _SysCounterInfo {
 
 
 typedef struct _SyncTrigger {
-    SyncCounter *pCounter;
+    SyncObject *pSync;
     CARD64	wait_value;	/* wait value */
     unsigned int value_type;     /* Absolute or Relative */
     unsigned int test_type;	/* transition or Comparision type */