diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 9344216..f97122a 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -797,6 +797,10 @@
 
 	/* we have to call this as early as possible after the MMIO base address is known */
 	intel_i830_init_gtt_entries();
+	if (intel_private.gtt_entries == 0) {
+		iounmap(intel_private.registers);
+		return -ENOMEM;
+	}
 
 	agp_bridge->gatt_table = NULL;
 
@@ -1279,6 +1283,11 @@
 
 	/* we have to call this as early as possible after the MMIO base address is known */
 	intel_i830_init_gtt_entries();
+	if (intel_private.gtt_entries == 0) {
+		iounmap(intel_private.gtt);
+		iounmap(intel_private.registers);
+		return -ENOMEM;
+	}
 
 	agp_bridge->gatt_table = NULL;
 
@@ -1387,6 +1396,11 @@
 
 	/* we have to call this as early as possible after the MMIO base address is known */
 	intel_i830_init_gtt_entries();
+	if (intel_private.gtt_entries == 0) {
+		iounmap(intel_private.gtt);
+		iounmap(intel_private.registers);
+		return -ENOMEM;
+	}
 
 	agp_bridge->gatt_table = NULL;