diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index dcd593766a64..d7deedf3548e 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -6,6 +6,8 @@
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  */
 
+#define pr_fmt(fmt) "ACPI: " fmt
+
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -574,7 +576,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 		goto end;
 	}
 
-	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
+	pr_info("%s [%s] (domain %04x %pR)\n",
 	       acpi_device_name(device), acpi_device_bid(device),
 	       root->segment, &root->secondary);