From d6a3e574497b8f4855a0bb9e5c1eb3e1b6ebb770 Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Thu, 13 Aug 2009 16:37:00 +1000
Subject: [PATCH] Xext: fix up wrong conditions for negative sync transitions.

If the counter had a value higher than the trigger value for a negative
transition, the trigger value did not get set.

The correct sequence of checks is:
if (positive transition)
   if (counter value < trigger value)
      set up trigger
if (negative transition)
   if (counter value > trigger value)
      set up trigger

Red Hat Bug 501601 <https://bugzilla.redhat.com/show_bug.cgi?id=501601>
---
 Xext/sync.c |   32 ++++++++++++++------------------
 1 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/Xext/sync.c b/Xext/sync.c
index 5f4ce56..667f8ab 100644
--- a/Xext/sync.c
+++ b/Xext/sync.c
@@ -962,28 +962,24 @@ SyncComputeBracketValues(SyncCounter *pCounter, Bool startOver)
 		pnewltval = &psci->bracket_less;
 	    }
 	}
-	else if ( (pTrigger->test_type == XSyncPositiveTransition &&
+	else if (pTrigger->test_type == XSyncNegativeTransition &&
 		   ct != XSyncCounterNeverIncreases)
-		 ||
-		 (pTrigger->test_type == XSyncNegativeTransition &&
+	{
+	    if (XSyncValueGreaterThan(pCounter->value, pTrigger->test_value) &&
+		XSyncValueGreaterThan(pTrigger->test_value, psci->bracket_less))
+	    {
+		psci->bracket_less = pTrigger->test_value;
+		pnewltval = &psci->bracket_less;
+	    }
+	}
+        else if (pTrigger->test_type == XSyncPositiveTransition &&
 		  ct != XSyncCounterNeverDecreases)
-		 )
 	{
-	    if (XSyncValueLessThan(pCounter->value, pTrigger->test_value))
+	    if (XSyncValueLessThan(pCounter->value, pTrigger->test_value) &&
+		XSyncValueLessThan(pTrigger->test_value, psci->bracket_greater))
 	    {
-		if (XSyncValueLessThan(pTrigger->test_value,
-				       psci->bracket_greater))
-		{
-		    psci->bracket_greater = pTrigger->test_value;
-		    pnewgtval = &psci->bracket_greater;
-		}
-		else
-		if (XSyncValueGreaterThan(pTrigger->test_value,
-					  psci->bracket_less))
-		{
-		    psci->bracket_less = pTrigger->test_value;
-		    pnewltval = &psci->bracket_less;
-		}
+		psci->bracket_greater = pTrigger->test_value;
+		pnewgtval = &psci->bracket_greater;
 	    }
 	}
     } /* end for each trigger */
-- 
1.6.3.rc1.2.g0164.dirty