diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 9c5d2a9..ef24cf7 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -269,15 +269,23 @@
 {
 	struct pci_dev *dev = child->self;
 	u8 io_base_lo, io_limit_lo;
-	unsigned long base, limit;
+	unsigned long io_mask, io_granularity, base, limit;
 	struct pci_bus_region region;
-	struct resource *res, res2;
+	struct resource *res;
+
+	io_mask = PCI_IO_RANGE_MASK;
+	io_granularity = 0x1000;
+	if (dev->io_window_1k) {
+		/* Support 1K I/O space granularity */
+		io_mask = PCI_IO_1K_RANGE_MASK;
+		io_granularity = 0x400;
+	}
 
 	res = child->resource[0];
 	pci_read_config_byte(dev, PCI_IO_BASE, &io_base_lo);
 	pci_read_config_byte(dev, PCI_IO_LIMIT, &io_limit_lo);
-	base = (io_base_lo & PCI_IO_RANGE_MASK) << 8;
-	limit = (io_limit_lo & PCI_IO_RANGE_MASK) << 8;
+	base = (io_base_lo & io_mask) << 8;
+	limit = (io_limit_lo & io_mask) << 8;
 
 	if ((io_base_lo & PCI_IO_RANGE_TYPE_MASK) == PCI_IO_RANGE_TYPE_32) {
 		u16 io_base_hi, io_limit_hi;
@@ -289,14 +297,9 @@
 
 	if (base <= limit) {
 		res->flags = (io_base_lo & PCI_IO_RANGE_TYPE_MASK) | IORESOURCE_IO;
-		res2.flags = res->flags;
 		region.start = base;
-		region.end = limit + 0xfff;
-		pcibios_bus_to_resource(dev, &res2, &region);
-		if (!res->start)
-			res->start = res2.start;
-		if (!res->end)
-			res->end = res2.end;
+		region.end = limit + io_granularity - 1;
+		pcibios_bus_to_resource(dev, res, &region);
 		dev_printk(KERN_DEBUG, &dev->dev, "  bridge window %pR\n", res);
 	}
 }