Index: kernel/generic/include/ddi/irq.h
===================================================================
--- kernel/generic/include/ddi/irq.h	(revision 557394294b6545575e0e9b328455da8ae4cf8a51)
+++ kernel/generic/include/ddi/irq.h	(revision 328f324bc169113023515c3003ef864c3c65b399)
@@ -122,4 +122,12 @@
 	 */
 	SPINLOCK_DECLARE(lock);
+	
+	/** Send EOI before processing the interrupt.
+	 *  This is essential for timer interrupt which
+	 *  has to be acknowledged before doing preemption
+	 *  to make sure another timer interrupt will
+	 *  be eventually generated.
+	 */
+	bool preack;
 
 	/** Unique device number. -1 if not yet assigned. */
@@ -128,5 +136,5 @@
 	/** Actual IRQ number. -1 if not yet assigned. */
 	inr_t inr;
-	/** Trigger level of the IRQ.*/
+	/** Trigger level of the IRQ. */
 	irq_trigger_t trigger;
 	/** Claim ownership of the IRQ. */