diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index c0ed235812a7..2bc9c1c0efb0 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -826,9 +826,14 @@ pci_add_map(device_t pcib, device_t bus, device_t dev,
 	 * If base is 0, then we have problems.  It is best to ignore
 	 * such entries for the moment.  These will be allocated later if
 	 * the driver specifically requests them.
+	 *
+	 * Similarlly treat maps whose values is the same as the test value
+	 * read back.  These maps have had all f's written to them by the
+	 * BIOS in an attempt to disable the resources.
 	 */
-	if (base == 0)
+	if (base == 0 || map == testval)
 		return 1;
+
 	/*
 	 * This code theoretically does the right thing, but has
 	 * undesirable side effects in some cases where peripherals