Messages in this thread Patch in this message | | | Subject | [PATCH] fix return value of i8042_aux_test_irq | From | Fernando Luis Vázquez Cao <> | Date | Thu, 26 Jul 2007 17:04:25 +0900 |
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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 <fernando@oss.ntt.co.jp> ---
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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