xirc2ps_cs irq return fix

diff -puN arch/i386/kernel/irq.c~irq-check-rate-limit arch/i386/kernel/irq.c
@@ -66,8 +66,12 @@
 /*
  * Controller mappings for all interrupt sources:
  */
-irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned =
-	{ [0 ... NR_IRQS-1] = { 0, &no_irq_type, NULL, 0, SPIN_LOCK_UNLOCKED}};
+irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
+	[0 ... NR_IRQS-1] = {
+		.handler = &no_irq_type,
+		.lock = SPIN_LOCK_UNLOCKED
+	}
+};
 
 static void register_irq_proc (unsigned int irq);
 

@@ -209,7 +213,6 @@ int handle_IRQ_event(unsigned int irq,
 {
 	int status = 1;	/* Force the "do bottom halves" bit */
 	int retval = 0;
-	struct irqaction *first_action = action;
 
 	if (!(action->flags & SA_INTERRUPT))
 		local_irq_enable();

@@ -222,30 +225,69 @@ int handle_IRQ_event(unsigned int irq,
 	if (status & SA_SAMPLE_RANDOM)
 		add_interrupt_randomness(irq);
 	local_irq_disable();
-	if (retval != 1) {
-		static int count = 100;
-		if (count) {
-			count--;
-			if (retval) {
-				printk("irq event %d: bogus retval mask %x\n",
-					irq, retval);
-			} else {
-				printk("irq %d: nobody cared!\n", irq);
-			}
-			dump_stack();
-			printk("handlers:\n");
-			action = first_action;
-			do {
-				printk("[<%p>]", action->handler);
-				print_symbol(" (%s)",
-					(unsigned long)action->handler);
-				printk("\n");
-				action = action->next;
-			} while (action);
+	return retval;
+}
+
+static void report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
+{
+	static int count = 100;
+	struct irqaction *action;
+
+	if (count) {
+		count--;
+		if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
+			printk("irq event %d: bogus return value %x\n",
+					irq, action_ret);
+		} else {
+			printk("irq %d: nobody cared!\n", irq);
 		}
+		dump_stack();
+		printk("handlers:\n");
+		action = desc->action;
+		do {
+			printk("[<%p>]", action->handler);
+			print_symbol(" (%s)",
+				(unsigned long)action->handler);
+			printk("\n");
+			action = action->next;
+		} while (action);
 	}
+}
 
-	return status;
+/*
+ * If 750 of the previous 1000 interrupts have not been handled then assume
+ * that the IRQ is stuck in some manner.  Drop a diagnostic and try to turn the
+ * IRQ off.
+ *
+ * Called under desc->lock
+ */
+static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret)
+{
+	if (action_ret != IRQ_HANDLED) {
+		desc->irqs_unhandled++;
+		if (action_ret != IRQ_NONE)
+			report_bad_irq(irq, desc, action_ret);
+	}
+
+	desc->irq_count++;
+	if (desc->irq_count < 1000)
+		return;
+
+	desc->irq_count = 0;
+	if (desc->irqs_unhandled > 750) {
+		/*
+		 * The interrupt is stuck
+		 */
+		report_bad_irq(irq, desc, action_ret);
+		/*
+		 * Now kill the IRQ
+		 */
+#if 0
+		desc->status |= IRQ_DISABLED;
+		desc->handler->disable(irq);
+#endif
+	}
+	desc->irqs_unhandled = 0;
 }
 
 /*

@@ -418,10 +460,12 @@ asmlinkage unsigned int do_IRQ(struct pt
 	 * SMP environment.
 	 */
 	for (;;) {
+		irqreturn_t action_ret;
+
 		spin_unlock(&desc->lock);
-		handle_IRQ_event(irq, &regs, action);
+		action_ret = handle_IRQ_event(irq, &regs, action);
 		spin_lock(&desc->lock);
-		
+		note_interrupt(irq, desc, action_ret);
 		if (likely(!(desc->status & IRQ_PENDING)))
 			break;
 		desc->status &= ~IRQ_PENDING;

diff -puN include/linux/irq.h~irq-check-rate-limit include/linux/irq.h
@@ -61,6 +61,8 @@ typedef struct {
 	hw_irq_controller *handler;
 	struct irqaction *action;	/* IRQ action list */
 	unsigned int depth;		/* nested irq disables */
+	unsigned int irq_count;		/* For detecting broken interrupts */
+	unsigned int irqs_unhandled;
 	spinlock_t lock;
 } ____cacheline_aligned irq_desc_t;