I made an interesting finding while testing the two patches below.
http://lkml.org/lkml/2007/7/19/685
http://lkml.org/lkml/2007/7/19/687
These patches modify the traditional CONFIG_DEBUG_KERNEL in such a way
that the request_irq prints a warning if after calling the handler it
returned IRQ_HANDLED .
The code looks like this:
int request_irq(unsigned int irq, irq_handler_t handler,
unsigned long irqflags, const char *devname, void
*dev_id)
.....
if (irqflags & IRQF_DISABLED) {
unsigned long flags;
local_irq_save(flags);
retval = handler(irq, dev_id);
local_irq_restore(flags);
} else
retval = handler(irq, dev_id);
if (retval == IRQ_HANDLED) {
printk(KERN_WARNING
"%s (IRQ %d) handled a spurious interrupt\n",
devname, irq);
}
.....
I discovered that i8042_aux_test_irq handles the "fake" interrupt,
which, in principle, is not correct because it obviously isn't a real
interrupt and it could have been a spurious interrupt as well.
The problem is that the interrupt handler unconditionally returns IRQ
handled, which does not seem correct. Anyway I am not very familiar with
this code so I may be missing the whole point. I would appreciate your
comments on this.
Thank you in advance.
Fernando
--
Do not return IRQ_HANDLED when we haven't handle the interrupt.
Signed-off-by: Fernando Luis Vazquez Cao <[EMAIL PROTECTED]>
---
diff -urNp linux-2.6.23-rc1-mm1-orig/drivers/input/serio/i8042.c
linux-2.6.23-rc1-mm1/drivers/input/serio/i8042.c
--- linux-2.6.23-rc1-mm1-orig/drivers/input/serio/i8042.c 2007-07-26
16:10:11.000000000 +0900
+++ linux-2.6.23-rc1-mm1/drivers/input/serio/i8042.c 2007-07-26
16:05:19.000000000 +0900
@@ -516,6 +516,7 @@ static irqreturn_t __devinit i8042_aux_t
{
unsigned long flags;
unsigned char str, data;
+ int ret;
spin_lock_irqsave(&i8042_lock, flags);
str = i8042_read_status();
@@ -524,10 +525,13 @@ static irqreturn_t __devinit i8042_aux_t
if (i8042_irq_being_tested &&
data == 0xa5 && (str & I8042_STR_AUXDATA))
complete(&i8042_aux_irq_delivered);
+ ret = 1;
}
+ else
+ ret = 0;
spin_unlock_irqrestore(&i8042_lock, flags);
- return IRQ_HANDLED;
+ return IRQ_RETVAL(ret);
}
/*
-
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