diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index abd575cfc759..ce1f2c85e20f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1275,6 +1275,12 @@ and is between 256 and 4096 characters. It is defined in the file
 				This sorting is done to get a device
 				order compatible with older (<= 2.4) kernels.
 		nobfsort	Don't sort PCI devices into breadth-first order.
+		cbiosize=nn[KMG]	The fixed amount of bus space which is
+				reserved for the CardBus bridge's IO window.
+				The default value is 256 bytes.
+		cbmemsize=nn[KMG]	The fixed amount of bus space which is
+				reserved for the CardBus bridge's memory
+				window. The default value is 64 megabytes.
 
 	pcmv=		[HW,PCMCIA] BadgePAD 4
 
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a7b869e24650..1e74e1ee8bd8 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -21,6 +21,12 @@
 
 unsigned int pci_pm_d3_delay = 10;
 
+#define DEFAULT_CARDBUS_IO_SIZE		(256)
+#define DEFAULT_CARDBUS_MEM_SIZE	(64*1024*1024)
+/* pci=cbmemsize=nnM,cbiosize=nn can override this */
+unsigned long pci_cardbus_io_size = DEFAULT_CARDBUS_IO_SIZE;
+unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE;
+
 /**
  * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
  * @bus: pointer to PCI bus structure to search
@@ -1333,6 +1339,10 @@ static int __devinit pci_setup(char *str)
 		if (*str && (str = pcibios_setup(str)) && *str) {
 			if (!strcmp(str, "nomsi")) {
 				pci_no_msi();
+			} else if (!strncmp(str, "cbiosize=", 9)) {
+				pci_cardbus_io_size = memparse(str + 9, &str);
+			} else if (!strncmp(str, "cbmemsize=", 10)) {
+				pci_cardbus_mem_size = memparse(str + 10, &str);
 			} else {
 				printk(KERN_ERR "PCI: Unknown option `%s'\n",
 						str);
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 89f3036f0de8..3554f3948814 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -36,13 +36,6 @@
 
 #define ROUND_UP(x, a)		(((x) + (a) - 1) & ~((a) - 1))
 
-/*
- * FIXME: IO should be max 256 bytes.  However, since we may
- * have a P2P bridge below a cardbus bridge, we need 4K.
- */
-#define CARDBUS_IO_SIZE		(256)
-#define CARDBUS_MEM_SIZE	(64*1024*1024)
-
 static void __devinit
 pbus_assign_resources_sorted(struct pci_bus *bus)
 {
@@ -415,12 +408,12 @@ pci_bus_size_cardbus(struct pci_bus *bus)
 	 * Reserve some resources for CardBus.  We reserve
 	 * a fixed amount of bus space for CardBus bridges.
 	 */
-	b_res[0].start = CARDBUS_IO_SIZE;
-	b_res[0].end = b_res[0].start + CARDBUS_IO_SIZE - 1;
+	b_res[0].start = pci_cardbus_io_size;
+	b_res[0].end = b_res[0].start + pci_cardbus_io_size - 1;
 	b_res[0].flags |= IORESOURCE_IO;
 
-	b_res[1].start = CARDBUS_IO_SIZE;
-	b_res[1].end = b_res[1].start + CARDBUS_IO_SIZE - 1;
+	b_res[1].start = pci_cardbus_io_size;
+	b_res[1].end = b_res[1].start + pci_cardbus_io_size - 1;
 	b_res[1].flags |= IORESOURCE_IO;
 
 	/*
@@ -440,16 +433,16 @@ pci_bus_size_cardbus(struct pci_bus *bus)
 	 * twice the size.
 	 */
 	if (ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM0) {
-		b_res[2].start = CARDBUS_MEM_SIZE;
-		b_res[2].end = b_res[2].start + CARDBUS_MEM_SIZE - 1;
+		b_res[2].start = pci_cardbus_mem_size;
+		b_res[2].end = b_res[2].start + pci_cardbus_mem_size - 1;
 		b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;
 
-		b_res[3].start = CARDBUS_MEM_SIZE;
-		b_res[3].end = b_res[3].start + CARDBUS_MEM_SIZE - 1;
+		b_res[3].start = pci_cardbus_mem_size;
+		b_res[3].end = b_res[3].start + pci_cardbus_mem_size - 1;
 		b_res[3].flags |= IORESOURCE_MEM;
 	} else {
-		b_res[3].start = CARDBUS_MEM_SIZE * 2;
-		b_res[3].end = b_res[3].start + CARDBUS_MEM_SIZE * 2 - 1;
+		b_res[3].start = pci_cardbus_mem_size * 2;
+		b_res[3].end = b_res[3].start + pci_cardbus_mem_size * 2 - 1;
 		b_res[3].flags |= IORESOURCE_MEM;
 	}
 }
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 98c8765a488e..2c4b6842dfb9 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -854,5 +854,8 @@ extern int pci_pci_problems;
 #define PCIPCI_ALIMAGIK		32	/* Need low latency setting */
 #define PCIAGP_FAIL		64	/* No PCI to AGP DMA */
 
+extern unsigned long pci_cardbus_io_size;
+extern unsigned long pci_cardbus_mem_size;
+
 #endif /* __KERNEL__ */
 #endif /* LINUX_PCI_H */