2 * linux/kernel/irq/spurious.c
4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
6 * This file contains spurious interrupt handling.
9 #include <linux/jiffies.h>
10 #include <linux/irq.h>
11 #include <linux/module.h>
12 #include <linux/kallsyms.h>
13 #include <linux/interrupt.h>
14 #include <linux/moduleparam.h>
15 #include <linux/timer.h>
17 static int irqfixup __read_mostly
;
19 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
20 static void poll_spurious_irqs(unsigned long dummy
);
21 static DEFINE_TIMER(poll_spurious_irq_timer
, poll_spurious_irqs
, 0, 0);
24 * Recovery handler for misrouted interrupts.
26 static int try_one_irq(int irq
, struct irq_desc
*desc
)
28 struct irqaction
*action
;
30 int work
= 0; /* Did we do work for a real IRQ */
32 spin_lock(&desc
->lock
);
33 /* Already running on another processor */
34 if (desc
->status
& IRQ_INPROGRESS
) {
36 * Already running: If it is shared get the other
37 * CPU to go looking for our mystery interrupt too
39 if (desc
->action
&& (desc
->action
->flags
& IRQF_SHARED
))
40 desc
->status
|= IRQ_PENDING
;
41 spin_unlock(&desc
->lock
);
44 /* Honour the normal IRQ locking */
45 desc
->status
|= IRQ_INPROGRESS
;
46 action
= desc
->action
;
47 spin_unlock(&desc
->lock
);
50 /* Only shared IRQ handlers are safe to call */
51 if (action
->flags
& IRQF_SHARED
) {
52 if (action
->handler(irq
, action
->dev_id
) ==
56 action
= action
->next
;
59 /* Now clean up the flags */
60 spin_lock(&desc
->lock
);
61 action
= desc
->action
;
64 * While we were looking for a fixup someone queued a real
65 * IRQ clashing with our walk:
67 while ((desc
->status
& IRQ_PENDING
) && action
) {
69 * Perform real IRQ processing for the IRQ we deferred
72 spin_unlock(&desc
->lock
);
73 handle_IRQ_event(irq
, action
);
74 spin_lock(&desc
->lock
);
75 desc
->status
&= ~IRQ_PENDING
;
77 desc
->status
&= ~IRQ_INPROGRESS
;
79 * If we did actual work for the real IRQ line we must let the
80 * IRQ controller clean up too
82 if (work
&& desc
->chip
&& desc
->chip
->end
)
84 spin_unlock(&desc
->lock
);
89 static int misrouted_irq(int irq
)
94 for (i
= 1; i
< nr_irqs
; i
++) {
95 struct irq_desc
*desc
;
97 if (i
== irq
) /* Already tried */
100 desc
= irq_to_desc(i
);
101 if (try_one_irq(i
, desc
))
104 /* So the caller can adjust the irq error counts */
108 static void poll_spurious_irqs(unsigned long dummy
)
111 for (i
= 1; i
< nr_irqs
; i
++) {
112 struct irq_desc
*desc
= irq_to_desc(i
);
115 /* Racy but it doesn't matter */
116 status
= desc
->status
;
118 if (!(status
& IRQ_SPURIOUS_DISABLED
))
121 try_one_irq(i
, desc
);
124 mod_timer(&poll_spurious_irq_timer
, jiffies
+ POLL_SPURIOUS_IRQ_INTERVAL
);
128 * If 99,900 of the previous 100,000 interrupts have not been handled
129 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
130 * and try to turn the IRQ off.
132 * (The other 100-of-100,000 interrupts may have been a correctly
133 * functioning device sharing an IRQ with the failing one)
135 * Called under desc->lock
139 __report_bad_irq(unsigned int irq
, struct irq_desc
*desc
,
140 irqreturn_t action_ret
)
142 struct irqaction
*action
;
144 if (action_ret
!= IRQ_HANDLED
&& action_ret
!= IRQ_NONE
) {
145 printk(KERN_ERR
"irq event %d: bogus return value %x\n",
148 printk(KERN_ERR
"irq %d: nobody cared (try booting with "
149 "the \"irqpoll\" option)\n", irq
);
152 printk(KERN_ERR
"handlers:\n");
154 action
= desc
->action
;
156 printk(KERN_ERR
"[<%p>]", action
->handler
);
157 print_symbol(" (%s)",
158 (unsigned long)action
->handler
);
160 action
= action
->next
;
165 report_bad_irq(unsigned int irq
, struct irq_desc
*desc
, irqreturn_t action_ret
)
167 static int count
= 100;
171 __report_bad_irq(irq
, desc
, action_ret
);
175 static inline int try_misrouted_irq(unsigned int irq
, struct irq_desc
*desc
, irqreturn_t action_ret
)
177 struct irqaction
*action
;
182 /* We didn't actually handle the IRQ - see if it was misrouted? */
183 if (action_ret
== IRQ_NONE
)
187 * But for 'irqfixup == 2' we also do it for handled interrupts if
188 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
189 * traditional PC timer interrupt.. Legacy)
198 * Since we don't get the descriptor lock, "action" can
199 * change under us. We don't really care, but we don't
200 * want to follow a NULL pointer. So tell the compiler to
201 * just load it once by using a barrier.
203 action
= desc
->action
;
205 return action
&& (action
->flags
& IRQF_IRQPOLL
);
208 void note_interrupt(unsigned int irq
, struct irq_desc
*desc
,
209 irqreturn_t action_ret
)
211 if (unlikely(action_ret
!= IRQ_HANDLED
)) {
213 * If we are seeing only the odd spurious IRQ caused by
214 * bus asynchronicity then don't eventually trigger an error,
215 * otherwise the couter becomes a doomsday timer for otherwise
218 if (time_after(jiffies
, desc
->last_unhandled
+ HZ
/10))
219 desc
->irqs_unhandled
= 1;
221 desc
->irqs_unhandled
++;
222 desc
->last_unhandled
= jiffies
;
223 if (unlikely(action_ret
!= IRQ_NONE
))
224 report_bad_irq(irq
, desc
, action_ret
);
227 if (unlikely(try_misrouted_irq(irq
, desc
, action_ret
))) {
228 int ok
= misrouted_irq(irq
);
229 if (action_ret
== IRQ_NONE
)
230 desc
->irqs_unhandled
-= ok
;
234 if (likely(desc
->irq_count
< 100000))
238 if (unlikely(desc
->irqs_unhandled
> 99900)) {
240 * The interrupt is stuck
242 __report_bad_irq(irq
, desc
, action_ret
);
246 printk(KERN_EMERG
"Disabling IRQ #%d\n", irq
);
247 desc
->status
|= IRQ_DISABLED
| IRQ_SPURIOUS_DISABLED
;
249 desc
->chip
->disable(irq
);
251 mod_timer(&poll_spurious_irq_timer
, jiffies
+ POLL_SPURIOUS_IRQ_INTERVAL
);
253 desc
->irqs_unhandled
= 0;
256 int noirqdebug __read_mostly
;
258 int noirqdebug_setup(char *str
)
261 printk(KERN_INFO
"IRQ lockup detection disabled\n");
266 __setup("noirqdebug", noirqdebug_setup
);
267 module_param(noirqdebug
, bool, 0644);
268 MODULE_PARM_DESC(noirqdebug
, "Disable irq lockup detection when true");
270 static int __init
irqfixup_setup(char *str
)
273 printk(KERN_WARNING
"Misrouted IRQ fixup support enabled.\n");
274 printk(KERN_WARNING
"This may impact system performance.\n");
279 __setup("irqfixup", irqfixup_setup
);
280 module_param(irqfixup
, int, 0644);
281 MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode 2: irqpoll mode");
283 static int __init
irqpoll_setup(char *str
)
286 printk(KERN_WARNING
"Misrouted IRQ fixup and polling support "
288 printk(KERN_WARNING
"This may significantly impact system "
293 __setup("irqpoll", irqpoll_setup
);