diff --git a/sys/dev/acpica/acpi_pcib_acpi.c b/sys/dev/acpica/acpi_pcib_acpi.c
index 2c056f30d735..e83e9576d61e 100644
--- a/sys/dev/acpica/acpi_pcib_acpi.c
+++ b/sys/dev/acpica/acpi_pcib_acpi.c
@@ -322,6 +322,8 @@ acpi_pcib_acpi_alloc_resource(device_t dev, device_t child, int type, int *rid,
      */
     if (type == SYS_RES_MEMORY && start == 0UL && end == ~0UL)
 	start = acpi_host_mem_start;
+    if (type == SYS_RES_IOPORT && start == 0UL && end == ~0UL)
+	start = 0x1000;
     return (bus_generic_alloc_resource(dev, child, type, rid, start, end,
 	count, flags));
 }
diff --git a/sys/i386/pci/pci_bus.c b/sys/i386/pci/pci_bus.c
index 8721d4a984f6..afd4bc68384c 100644
--- a/sys/i386/pci/pci_bus.c
+++ b/sys/i386/pci/pci_bus.c
@@ -503,6 +503,8 @@ legacy_pcib_alloc_resource(device_t dev, device_t child, int type, int *rid,
      */
     if (type == SYS_RES_MEMORY && start == 0UL && end == ~0UL)
 	start = legacy_host_mem_start;
+    if (type == SYS_RES_IOPORT && start == 0UL && end == ~0UL)
+	start = 0x1000;
     return (bus_generic_alloc_resource(dev, child, type, rid, start, end,
 	count, flags));
 }