From a87f16658700e61174d2d4268b19f3e833ff1f94 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sat, 1 Jul 2006 22:30:08 +0100
Subject: [PATCH] --- yaml --- r: 31711 b: refs/heads/master c:
 f8b5473fcbddbfde827ecf82aa0e81fa2a878220 h: refs/heads/master i:   31709:
 f92962aeb95c0ec0f4871f3671d58a7c75374260   31707:
 c396189f118c07eda679ee77c1b400f403c55fbe   31703:
 d5bd09f43089f5e6a86f0a90927f10f6659d3d45   31695:
 85ccaf0a8f77bd2975473d6cf0a39e160d257a38   31679:
 ce0e63dbd7a2d8fbd101d0d64d296a21b309edeb v: v3

---
 [refs]                    |  2 +-
 trunk/include/linux/irq.h |  3 ++-
 trunk/kernel/irq/chip.c   | 15 ++++++++++++---
 trunk/kernel/irq/handle.c | 16 ++++++++++++++++
 4 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index f3800b034c4f..89acef2d531f 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a2166abd06e7a9fd34eb18b7b27da18c6146e6ef
+refs/heads/master: f8b5473fcbddbfde827ecf82aa0e81fa2a878220
diff --git a/trunk/include/linux/irq.h b/trunk/include/linux/irq.h
index 0832149cdb18..00b6ef8b2f93 100644
--- a/trunk/include/linux/irq.h
+++ b/trunk/include/linux/irq.h
@@ -348,8 +348,9 @@ extern int noirqdebug_setup(char *str);
 /* Checks whether the interrupt can be requested by request_irq(): */
 extern int can_request_irq(unsigned int irq, unsigned long irqflags);
 
-/* Dummy irq-chip implementation: */
+/* Dummy irq-chip implementations: */
 extern struct irq_chip no_irq_chip;
+extern struct irq_chip dummy_irq_chip;
 
 extern void
 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
diff --git a/trunk/kernel/irq/chip.c b/trunk/kernel/irq/chip.c
index 4a0952d9458b..54105bdfe20d 100644
--- a/trunk/kernel/irq/chip.c
+++ b/trunk/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/trunk/kernel/irq/handle.c b/trunk/kernel/irq/handle.c
index 961b87591731..e71266c3803e 100644
--- a/trunk/kernel/irq/handle.c
+++ b/trunk/kernel/irq/handle.c
@@ -95,6 +95,22 @@ struct irq_chip no_irq_chip = {
 	.end		= noop,
 };
 
+/*
+ * 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:
  */