--- a/drivers/xen/pciback/conf_space_header.c	2007-05-18 16:45:21.000000000 +0200
+++ b/drivers/xen/pciback/conf_space_header.c	2007-07-10 01:05:57.165749185 +0200
@@ -75,8 +75,15 @@
 	 */
 	if (value == ~PCI_ROM_ADDRESS_ENABLE)
 		bar->which = 1;
-	else
+	else {
+		u32 tmpval;
+		pci_read_config_dword(dev, offset, &tmpval);
+		if(tmpval != bar->val && value == bar->val) {
+			/* We are trying to restore bar value. This should be allowed. */
+			pci_write_config_dword(dev, offset, bar->val);
+		}
 		bar->which = 0;
+	}
 
 	/* Do we need to support enabling/disabling the rom address here? */
 
@@ -102,8 +109,15 @@
 	 */
 	if (value == ~0)
 		bar->which = 1;
-	else
+	else {
+		u32 tmpval;
+		pci_read_config_dword(dev, offset, &tmpval);
+		if(tmpval != bar->val && value == bar->val) {
+			/* We are trying to restore bar value. This should be allowed. */
+			pci_write_config_dword(dev, offset, bar->val);
+		}
 		bar->which = 0;
+	}
 
 	return 0;
 }