diff --git a/Xi/selectev.c b/Xi/selectev.c
index d3670ab1b..53d8f7408 100644
--- a/Xi/selectev.c
+++ b/Xi/selectev.c
@@ -106,10 +106,10 @@ HandleDevicePresenceMask(ClientPtr client, WindowPtr win,
     if (mask == 0)
         return Success;
 
-    /* We always only use mksidx = 0 for events not bound to
+    /* We always only use mksidx = MAX_DEVICES for events not bound to
      * devices */
 
-    if (AddExtensionClient (win, client, mask, 0) != Success)
+    if (AddExtensionClient (win, client, mask, MAX_DEVICES) != Success)
         return BadAlloc;
 
     RecalculateDeviceDeliverableEvents(win);
diff --git a/dix/devices.c b/dix/devices.c
index 91a43f342..0a68c0e61 100644
--- a/dix/devices.c
+++ b/dix/devices.c
@@ -275,7 +275,7 @@ EnableDevice(DeviceIntPtr dev)
     ev.time = currentTime.milliseconds;
     ev.devchange = DeviceEnabled;
     ev.deviceid = dev->id;
-    dummyDev.id = 0;
+    dummyDev.id = MAX_DEVICES;
     SendEventToAllWindows(&dummyDev, DevicePresenceNotifyMask,
                           (xEvent *) &ev, 1);
 
@@ -339,7 +339,7 @@ DisableDevice(DeviceIntPtr dev)
     ev.time = currentTime.milliseconds;
     ev.devchange = DeviceDisabled;
     ev.deviceid = dev->id;
-    dummyDev.id = 0;
+    dummyDev.id = MAX_DEVICES;
     SendEventToAllWindows(&dummyDev, DevicePresenceNotifyMask,
                           (xEvent *) &ev, 1);
 
@@ -379,6 +379,7 @@ ActivateDevice(DeviceIntPtr dev)
     ev.deviceid = dev->id;
 
     memset(&dummyDev, 0, sizeof(DeviceIntRec));
+    dummyDev.id = MAX_DEVICES;
     SendEventToAllWindows(&dummyDev, DevicePresenceNotifyMask,
                           (xEvent *) &ev, 1);
 
@@ -937,7 +938,7 @@ RemoveDevice(DeviceIntPtr dev)
         ev.time = currentTime.milliseconds;
         ev.devchange = DeviceRemoved;
         ev.deviceid = deviceid;
-        dummyDev.id = 0;
+        dummyDev.id = MAX_DEVICES;
         SendEventToAllWindows(&dummyDev, DevicePresenceNotifyMask,
                               (xEvent *) &ev, 1);
     }
diff --git a/include/inputstr.h b/include/inputstr.h
index 4c7ec2eb9..e5de6fc31 100644
--- a/include/inputstr.h
+++ b/include/inputstr.h
@@ -66,7 +66,7 @@ SOFTWARE.
 
 #define MAX_DEVICES	20
 
-#define EMASKSIZE	MAX_DEVICES
+#define EMASKSIZE	MAX_DEVICES + 1
 
 extern DevPrivateKey CoreDevicePrivateKey;