diff --git a/arch/mips/kernel/i8259.c b/arch/mips/kernel/i8259.c
index 9c79703..fd7f4ba 100644
--- a/arch/mips/kernel/i8259.c
+++ b/arch/mips/kernel/i8259.c
@@ -47,11 +47,7 @@ static struct irq_chip i8259A_chip = {
 /*
  * This contains the irq mask for both 8259A irq controllers,
  */
-static unsigned int cached_irq_mask = 0xffff;
-
-#define cached_master_mask	(cached_irq_mask)
-#define cached_slave_mask	(cached_irq_mask >> 8)
-
+unsigned int cached_irq_mask = 0xffff;
 void disable_8259A_irq(unsigned int irq)
 {
 	unsigned int mask;
diff --git a/include/asm-mips/i8259.h b/include/asm-mips/i8259.h
index e88a016..e7dcf7b 100644
--- a/include/asm-mips/i8259.h
+++ b/include/asm-mips/i8259.h
@@ -37,11 +37,55 @@
 
 extern spinlock_t i8259A_lock;
 
+extern unsigned int cached_irq_mask;
+#define cached_master_mask	(cached_irq_mask)
+#define cached_slave_mask	(cached_irq_mask >> 8)
+
 extern void init_8259A(int auto_eoi);
 extern void enable_8259A_irq(unsigned int irq);
 extern void disable_8259A_irq(unsigned int irq);
 
 extern void init_i8259_irqs(void);
+#define CONFIG_NO_INTERRUPT_ACK
+#ifdef CONFIG_NO_INTERRUPT_ACK
+static inline int _byte_ffs(u8 word)
+{
+	int num = 0;
+	if ((word & 0xf) == 0) {
+		num += 4;
+		word >>= 4;
+	}
+	if ((word & 0x3) == 0) {
+		num += 2;
+		word >>= 2;
+	}
+	if ((word & 0x1) == 0)
+		num += 1;
+	return num;
+}
+
+static inline int read_irq(int port)
+{
+	int irq;
+	outb(0x0A, port);
+	if (port == PIC_MASTER_CMD) {
+		irq = inb(port) & ~cached_master_mask;
+	} else {
+		irq = inb(port) & ~cached_slave_mask;
+	}
+	if (irq == 0)
+		return -1;
+	else
+		return _byte_ffs(irq);
+}
+#else
+static inline int read_irq(int port)
+{
+	/* Perform an interrupt acknowledge cycle on controller 1. */
+	outb(0x0C, port);		/* prepare for poll */
+	return inb(port) & 7;
+}
+#endif
 
 /*
  * Do the traditional i8259 interrupt polling thing.  This is for the few
@@ -54,18 +98,16 @@ static inline int i8259_irq(void)
 
 	spin_lock(&i8259A_lock);
 
-	/* Perform an interrupt acknowledge cycle on controller 1. */
-	outb(0x0C, PIC_MASTER_CMD);		/* prepare for poll */
-	irq = inb(PIC_MASTER_CMD) & 7;
+	irq = read_irq(PIC_MASTER_CMD);
 	if (irq == PIC_CASCADE_IR) {
 		/*
 		 * Interrupt is cascaded so perform interrupt
 		 * acknowledge on controller 2.
 		 */
-		outb(0x0C, PIC_SLAVE_CMD);		/* prepare for poll */
-		irq = (inb(PIC_SLAVE_CMD) & 7) + 8;
-	}
+		irq = read_irq(PIC_SLAVE_CMD) + 8;
+	} 
 
+#ifndef CONFIG_NO_INTERRUPT_ACK
 	if (unlikely(irq == 7)) {
 		/*
 		 * This may be a spurious interrupt.
@@ -78,6 +120,11 @@ static inline int i8259_irq(void)
 		if(~inb(PIC_MASTER_ISR) & 0x80)
 			irq = -1;
 	}
+#else
+	if (cached_irq_mask & (1 << irq)) {
+		irq = -1;
+	}
+#endif
 
 	spin_unlock(&i8259A_lock);