diff --git a/include/linux/irq.h b/include/linux/irq.h
index 44657197fcb03de46c060e7634c73f3e126038d7..efc88538b2bae91a854e9bf3fbffc4832c77d7e4 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -140,6 +140,7 @@ struct irq_chip {
  * @wake_depth:		enable depth, for multiple set_irq_wake() callers
  * @irq_count:		stats field to detect stalled irqs
  * @irqs_unhandled:	stats field for spurious unhandled interrupts
+ * @last_unhandled:	aging timer for unhandled count
  * @lock:		locking for SMP
  * @affinity:		IRQ affinity on SMP
  * @cpu:		cpu index useful for balancing