diff --git a/[refs] b/[refs]
index 5e1df7b68a59..f94a749eb581 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 20c8c2106305729e7d5e06f6c3d390e965a3dd34
+refs/heads/master: beeca08738c4c4024c81a591812bfe38f8c436c0
diff --git a/trunk/kernel/irq/handle.c b/trunk/kernel/irq/handle.c
index 3ff7b925c387..51df337b37db 100644
--- a/trunk/kernel/irq/handle.c
+++ b/trunk/kernel/irq/handle.c
@@ -117,14 +117,16 @@ fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs)
 		/*
 		 * No locking required for CPU-local interrupts:
 		 */
-		desc->handler->ack(irq);
+		if (desc->handler->ack)
+			desc->handler->ack(irq);
 		action_ret = handle_IRQ_event(irq, regs, desc->action);
 		desc->handler->end(irq);
 		return 1;
 	}
 
 	spin_lock(&desc->lock);
-	desc->handler->ack(irq);
+	if (desc->handler->ack)
+		desc->handler->ack(irq);
 	/*
 	 * REPLAY is when Linux resends an IRQ that was dropped earlier
 	 * WAITING is used by probe to mark irqs that are being tested