diff --git a/hw/xfree86/common/xf86Bus.c b/hw/xfree86/common/xf86Bus.c
index 8382d911a..0d732d0b1 100644
--- a/hw/xfree86/common/xf86Bus.c
+++ b/hw/xfree86/common/xf86Bus.c
@@ -428,6 +428,9 @@ xf86GetEntityInfo(int entityIndex)
     EntityInfoPtr pEnt;
     int i;
     
+    if (entityIndex == -1)
+	return NULL;
+
     if (entityIndex >= xf86NumEntities)
 	return NULL;
     
diff --git a/hw/xfree86/common/xf86fbBus.c b/hw/xfree86/common/xf86fbBus.c
index a18963991..90e6eb0b6 100644
--- a/hw/xfree86/common/xf86fbBus.c
+++ b/hw/xfree86/common/xf86fbBus.c
@@ -57,6 +57,13 @@ xf86ClaimFbSlot(DriverPtr drvp, int chipset, GDevPtr dev, Bool active)
 {
     EntityPtr p;
     int num;
+
+    if (pciSlotClaimed)
+	return -1;
+#if defined(__sparc__) || defined (__sparc64__)
+    if (sbusSlotClaimed)
+	return -1;
+#endif
     
     num = xf86AllocateEntity();
     p = xf86Entities[num];