diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2fe1d690eb1..a4a96826d9e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -682,7 +682,34 @@ static void pci_read_irq(struct pci_dev *dev)
 	dev->irq = irq;
 }
 
-#define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
+static void change_legacy_io_resource(struct pci_dev * dev, unsigned index,
+                                      unsigned start, unsigned end)
+{
+	unsigned base = start & PCI_BASE_ADDRESS_IO_MASK;
+	unsigned len = (end | ~PCI_BASE_ADDRESS_IO_MASK) - base + 1;
+
+	/*
+	 * Some X versions get confused when the BARs reported through
+	 * /sys or /proc differ from those seen in config space, thus
+	 * try to update the config space values, too.
+	 */
+	if (!(pci_resource_flags(dev, index) & IORESOURCE_IO))
+		printk(KERN_WARNING "%s: cannot adjust BAR%u (not I/O)\n",
+		       pci_name(dev), index);
+	else if (pci_resource_len(dev, index) != len)
+		printk(KERN_WARNING "%s: cannot adjust BAR%u (size %04X)\n",
+		       pci_name(dev), index, (unsigned)pci_resource_len(dev, index));
+	else {
+		printk(KERN_INFO "%s: trying to change BAR%u from %04X to %04X\n",
+		       pci_name(dev), index,
+		       (unsigned)pci_resource_start(dev, index), base);
+		pci_write_config_dword(dev, PCI_BASE_ADDRESS_0 + index * 4, base);
+	}
+	pci_resource_start(dev, index) = start;
+	pci_resource_end(dev, index)   = end;
+	pci_resource_flags(dev, index) =
+		IORESOURCE_IO | IORESOURCE_PCI_FIXED | PCI_BASE_ADDRESS_SPACE_IO;
+}
 
 /**
  * pci_setup_device - fill in class and map information of a device
@@ -735,20 +762,12 @@ static int pci_setup_device(struct pci_dev * dev)
 			u8 progif;
 			pci_read_config_byte(dev, PCI_CLASS_PROG, &progif);
 			if ((progif & 1) == 0) {
-				dev->resource[0].start = 0x1F0;
-				dev->resource[0].end = 0x1F7;
-				dev->resource[0].flags = LEGACY_IO_RESOURCE;
-				dev->resource[1].start = 0x3F6;
-				dev->resource[1].end = 0x3F6;
-				dev->resource[1].flags = LEGACY_IO_RESOURCE;
+				change_legacy_io_resource(dev, 0, 0x1F0, 0x1F7);
+				change_legacy_io_resource(dev, 1, 0x3F6, 0x3F6);
 			}
 			if ((progif & 4) == 0) {
-				dev->resource[2].start = 0x170;
-				dev->resource[2].end = 0x177;
-				dev->resource[2].flags = LEGACY_IO_RESOURCE;
-				dev->resource[3].start = 0x376;
-				dev->resource[3].end = 0x376;
-				dev->resource[3].flags = LEGACY_IO_RESOURCE;
+				change_legacy_io_resource(dev, 2, 0x170, 0x177);
+				change_legacy_io_resource(dev, 3, 0x376, 0x376);
 			}
 		}
 		break;