diff --git a/dix/devices.c b/dix/devices.c
index d386f41..fe67faf 100644
--- a/dix/devices.c
+++ b/dix/devices.c
@@ -108,14 +108,15 @@ DeviceSetProperty(DeviceIntPtr dev, Atom property, XIPropertyValuePtr prop,
 {
     if (property == XIGetKnownProperty(XI_PROP_ENABLED))
     {
-        if (prop->format != 8 || prop->type != XA_INTEGER || prop->size != 1)
+        if (prop->format != 8 * sizeof(dev->enabled) ||
+            prop->type != XA_INTEGER || prop->size != 1)
             return BadValue;
 
         if (!checkonly)
         {
-            if ((*((CARD8*)prop->data)) && !dev->enabled)
+            if ((*((Bool*)prop->data)) && !dev->enabled)
                 EnableDevice(dev);
-            else if (!(*((CARD8*)prop->data)) && dev->enabled)
+            else if (!(*((Bool*)prop->data)) && dev->enabled)
                 DisableDevice(dev);
         }
     }
@@ -184,8 +185,8 @@ AddInputDevice(ClientPtr client, DeviceProc deviceProc, Bool autoStart)
     dev->next = NULL;
 
     XIChangeDeviceProperty(dev, XIGetKnownProperty(XI_PROP_ENABLED),
-                           XA_INTEGER, 8, PropModeReplace, 1, &dev->enabled,
-                           FALSE);
+                           XA_INTEGER, 8 * sizeof(dev->enabled),
+                           PropModeReplace, 1, &dev->enabled, FALSE);
     XISetDevicePropertyDeletable(dev, XIGetKnownProperty(XI_PROP_ENABLED), FALSE);
     XIRegisterPropertyHandler(dev, DeviceSetProperty, NULL, NULL);
 
@@ -275,8 +276,8 @@ EnableDevice(DeviceIntPtr dev)
     dev->next = NULL;
 
     XIChangeDeviceProperty(dev, XIGetKnownProperty(XI_PROP_ENABLED),
-                           XA_INTEGER, 8, PropModeReplace, 1, &dev->enabled,
-                           TRUE);
+                           XA_INTEGER, 8 * sizeof(dev->enabled),
+                           PropModeReplace, 1, &dev->enabled, TRUE);
 
     ev.type = DevicePresenceNotify;
     ev.time = currentTime.milliseconds;
@@ -351,8 +352,8 @@ DisableDevice(DeviceIntPtr dev)
     inputInfo.off_devices = dev;
 
     XIChangeDeviceProperty(dev, XIGetKnownProperty(XI_PROP_ENABLED),
-                           XA_INTEGER, 8, PropModeReplace, 1, &dev->enabled,
-                           TRUE);
+                           XA_INTEGER, 8 * sizeof(dev->enabled),
+                           PropModeReplace, 1, &dev->enabled, TRUE);
 
     ev.type = DevicePresenceNotify;
     ev.time = currentTime.milliseconds;