diff -r e6c966b3a4d8 xen/arch/x86/acpi/cpu_idle.c
--- a/xen/arch/x86/acpi/cpu_idle.c	Thu Jul 30 17:56:23 2009 +0100
+++ b/xen/arch/x86/acpi/cpu_idle.c	Fri Jul 31 11:34:35 2009 +0100
@@ -102,6 +102,7 @@
 {
     unsigned int cpu;
 
+    printk("'%c' pressed -> printing ACPI Cx structures\n", key);
     for_each_online_cpu ( cpu )
         if (processor_powers[cpu])
             print_acpi_power(cpu, processor_powers[cpu]);
@@ -110,7 +111,7 @@
 static int __init cpu_idle_key_init(void)
 {
     register_keyhandler(
-        'c', dump_cx,        "dump cx structures");
+        'c', dump_cx,        "dump ACPI Cx structures");
     return 0;
 }
 __initcall(cpu_idle_key_init);