diff --git a/drivers/acpi/motherboard.c b/drivers/acpi/motherboard.c
index 2934475d67d605a540ee4a58d3ef11ccda10c3c8..61ea70742d4912863df0fe4a25f01c1a98d54829 100644
--- a/drivers/acpi/motherboard.c
+++ b/drivers/acpi/motherboard.c
@@ -43,7 +43,7 @@ ACPI_MODULE_NAME		("acpi_motherboard")
  */
 #define IS_RESERVED_ADDR(base, len) \
 	(((len) > 0) && ((base) > 0) && ((base) + (len) < IO_SPACE_LIMIT) \
-	&& ((base) + (len) > 0x1000))
+	&& ((base) + (len) > PCIBIOS_MIN_IO))
 
 /*
  * Clearing the flag (IORESOURCE_BUSY) allows drivers to use
diff --git a/include/asm-i386/pci.h b/include/asm-i386/pci.h
index 2cbab30734d6d3e655ebd74fc3333a1d0234beed..78c85985aee36901c8b6369372643b52f3d94b65 100644
--- a/include/asm-i386/pci.h
+++ b/include/asm-i386/pci.h
@@ -18,9 +18,11 @@ extern unsigned int pcibios_assign_all_busses(void);
 #define pcibios_scan_all_fns(a, b)	0
 
 extern unsigned long pci_mem_start;
-#define PCIBIOS_MIN_IO		0x4000
+#define PCIBIOS_MIN_IO		0x1000
 #define PCIBIOS_MIN_MEM		(pci_mem_start)
 
+#define PCIBIOS_MIN_CARDBUS_IO	0x4000
+
 void pcibios_config_init(void);
 struct pci_bus * pcibios_scan_root(int bus);
 
diff --git a/include/asm-x86_64/pci.h b/include/asm-x86_64/pci.h
index 9c4527eb55e270ef3106ca447def0a25a1cf83e8..eeb3088a1c9e3d2fbbff1140b94fad85c69777f9 100644
--- a/include/asm-x86_64/pci.h
+++ b/include/asm-x86_64/pci.h
@@ -22,9 +22,11 @@ extern unsigned int pcibios_assign_all_busses(void);
 extern int no_iommu, force_iommu;
 
 extern unsigned long pci_mem_start;
-#define PCIBIOS_MIN_IO		0x4000
+#define PCIBIOS_MIN_IO		0x1000
 #define PCIBIOS_MIN_MEM		(pci_mem_start)
 
+#define PCIBIOS_MIN_CARDBUS_IO	0x4000
+
 void pcibios_config_init(void);
 struct pci_bus * pcibios_scan_root(int bus);
 extern int (*pci_config_read)(int seg, int bus, int dev, int fn, int reg, int len, u32 *value);