diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index cf57fe7..b50386d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -156,6 +156,8 @@
 	return flags;
 }
 
+#define PCI_COMMAND_DECODE_ENABLE	(PCI_COMMAND_MEMORY | PCI_COMMAND_IO)
+
 /**
  * pci_read_base - read a PCI BAR
  * @dev: the PCI device
@@ -178,8 +180,10 @@
 	/* No printks while decoding is disabled! */
 	if (!dev->mmio_always_on) {
 		pci_read_config_word(dev, PCI_COMMAND, &orig_cmd);
-		pci_write_config_word(dev, PCI_COMMAND,
-			orig_cmd & ~(PCI_COMMAND_MEMORY | PCI_COMMAND_IO));
+		if (orig_cmd & PCI_COMMAND_DECODE_ENABLE) {
+			pci_write_config_word(dev, PCI_COMMAND,
+				orig_cmd & ~PCI_COMMAND_DECODE_ENABLE);
+		}
 	}
 
 	res->name = pci_name(dev);
@@ -293,7 +297,8 @@
 fail:
 	res->flags = 0;
 out:
-	if (!dev->mmio_always_on)
+	if (!dev->mmio_always_on &&
+	    (orig_cmd & PCI_COMMAND_DECODE_ENABLE))
 		pci_write_config_word(dev, PCI_COMMAND, orig_cmd);
 
 	if (bar_too_big)