From f5d89470f91f2e67eeaf350c730ae8412c3a98e3 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 19 Apr 2012 12:06:13 +0200
Subject: [PATCH] genirq: Be more informative on irq type mismatch

We require that shared interrupts agree on a few flag settings. Right
now we silently return with an error code without giving any hint why
we reject it.

Make the printout unconditionally and actually useful by printing the
flags of the new and the already registered action.

Convert all printks to pr_* and use a proper prefix while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/irq/manage.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 9a35ace38bb1..585f6381f8e4 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -565,8 +565,8 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 		 * IRQF_TRIGGER_* but the PIC does not support multiple
 		 * flow-types?
 		 */
-		pr_debug("No set_type function for IRQ %d (%s)\n", irq,
-				chip ? (chip->name ? : "unknown") : "unknown");
+		pr_debug("genirq: No set_type function for IRQ %d (%s)\n", irq,
+			 chip ? (chip->name ? : "unknown") : "unknown");
 		return 0;
 	}
 
@@ -600,7 +600,7 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 		ret = 0;
 		break;
 	default:
-		pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
+		pr_err("genirq: Setting trigger mode %lu for irq %u failed (%pF)\n",
 		       flags, irq, chip->irq_set_type);
 	}
 	if (unmask)
@@ -837,8 +837,7 @@ void exit_irq_thread(void)
 
 	action = kthread_data(tsk);
 
-	printk(KERN_ERR
-	       "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+	pr_err("genirq: exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 	       tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
 
 	desc = irq_to_desc(action->irq);
@@ -878,7 +877,6 @@ static int
 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 {
 	struct irqaction *old, **old_ptr;
-	const char *old_name = NULL;
 	unsigned long flags, thread_mask = 0;
 	int ret, nested, shared = 0;
 	cpumask_var_t mask;
@@ -972,10 +970,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 		 */
 		if (!((old->flags & new->flags) & IRQF_SHARED) ||
 		    ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
-		    ((old->flags ^ new->flags) & IRQF_ONESHOT)) {
-			old_name = old->name;
+		    ((old->flags ^ new->flags) & IRQF_ONESHOT))
 			goto mismatch;
-		}
 
 		/* All handlers must agree on per-cpuness */
 		if ((old->flags & IRQF_PERCPU) !=
@@ -1099,7 +1095,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 
 		if (nmsk != omsk)
 			/* hope the handler works with current  trigger mode */
-			pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
+			pr_warning("genirq: irq %d uses trigger mode %u; requested %u\n",
 				   irq, nmsk, omsk);
 	}
 
@@ -1136,14 +1132,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 	return 0;
 
 mismatch:
-#ifdef CONFIG_DEBUG_SHIRQ
 	if (!(new->flags & IRQF_PROBE_SHARED)) {
-		printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
-		if (old_name)
-			printk(KERN_ERR "current handler: %s\n", old_name);
+		pr_err("genirq: Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
+		       irq, new->flags, new->name, old->flags, old->name);
+#ifdef CONFIG_DEBUG_SHIRQ
 		dump_stack();
-	}
 #endif
+	}
 	ret = -EBUSY;
 
 out_mask: