2 files changed, 41 insertions, 3 deletions
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 4a0952d9458b..54105bdfe20d 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -462,9 +462,18 @@ __set_irq_handler(unsigned int irq,
 	if (!handle)
 		handle = handle_bad_irq;
 
-	if (is_chained && desc->chip == &no_irq_chip)
-		printk(KERN_WARNING "Trying to install "
-		       "chained interrupt type for IRQ%d\n", irq);
+	if (desc->chip == &no_irq_chip) {
+		printk(KERN_WARNING "Trying to install %sinterrupt handler "
+		       "for IRQ%d\n", is_chained ? "chained " : " ", irq);
+		/*
+		 * Some ARM implementations install a handler for really dumb
+		 * interrupt hardware without setting an irq_chip. This worked
+		 * with the ARM no_irq_chip but the check in setup_irq would
+		 * prevent us to setup the interrupt at all. Switch it to
+		 * dummy_irq_chip for easy transition.
+		 */
+		desc->chip = &dummy_irq_chip;
+	}
 
 	spin_lock_irqsave(&desc->lock, flags);
 
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 6070e0464690..6d8b30114961 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -16,6 +16,10 @@
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
 
+#if defined(CONFIG_NO_IDLE_HZ) && defined(CONFIG_ARM)
+#include <asm/dyntick.h>
+#endif
+
 #include "internals.h"
 
 /**
@@ -92,6 +96,22 @@ struct irq_chip no_irq_chip = {
 };
 
 /*
+ * Generic dummy implementation which can be used for
+ * real dumb interrupt sources
+ */
+struct irq_chip dummy_irq_chip = {
+	.name		= "dummy",
+	.startup	= noop_ret,
+	.shutdown	= noop,
+	.enable		= noop,
+	.disable	= noop,
+	.ack		= noop,
+	.mask		= noop,
+	.unmask		= noop,
+	.end		= noop,
+};
+
+/*
  * Special, empty irq handler:
  */
 irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
@@ -113,6 +133,15 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
 	irqreturn_t ret, retval = IRQ_NONE;
 	unsigned int status = 0;
 
+#if defined(CONFIG_NO_IDLE_HZ) && defined(CONFIG_ARM)
+	if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) {
+		write_seqlock(&xtime_lock);
+		if (system_timer->dyn_tick->state & DYN_TICK_ENABLED)
+			system_timer->dyn_tick->handler(irq, 0, regs);
+		write_sequnlock(&xtime_lock);
+	}
+#endif
+
 	if (!(action->flags & IRQF_DISABLED))
 		local_irq_enable();