--- ./xorg-server-1.12.1/dix/getevents.c	2012-03-31 09:45:56.000000000 +0700
+++ ./getevents.c	2012-04-27 07:52:56.824498248 +0700
@@ -1435,13 +1435,15 @@
     if ((incr > 0 && delta < 0) || (incr < 0 && delta > 0))
         b--;                    /* we're scrolling up or left → button 4 or 6 */
 
-    while (fabs(delta) >= fabs(incr)) {
+    incr = fabs(incr);
+
+    while (fabs(delta) >= incr) {
         int nev_tmp;
 
         if (delta > 0)
-            delta -= fabs(incr);
+            delta -= incr;
         else if (delta < 0)
-            delta += fabs(incr);
+            delta += incr;
 
         /* fill_pointer_events() generates four events: one normal and one raw
          * event for button press and button release.
@@ -1462,6 +1464,14 @@
                 num_events += nev_tmp;
             }
         }
+        else
+        {
+            if (incr > 0)
+                delta = fmod(delta,incr);
+            else
+                delta = 0;
+            break;
+        }
     }
 
     /* We emulated, update last.scroll */