I have an ISR that seems to happen twice for each
interrupt. I have verified that interrupt pin is
deactivated when I receive the second interrupt.
I understand that that Linux has some sort of queuing
for interrupts, but have not be able to find much
information on this. How do I stop this second
interrupt?
The following code is for a Linux 2.4 kernel.
_syscall1(int, nice, int, increment)
/*===========================================================================
===========================================================================*/
static int wait_4_irq_thread(void *unused)
{
/*
* This thread doesn't need any user-level access,
* so get rid of all our resources
*/
daemonize();
reparent_to_init();
/* Setup a nice name */
strcpy(current->comm, "16is7xx");
/* this is an isr so let's get rude and set it as
top priority */
nice(-40);
/* Send me a signal to get me die (for debugging) */
do { wait_event_interruptible(is7xx_wait,
(is7xx_interrupt_dev_id != NULL));
if(is7xx_interrupt_dev_id != NULL) {
is7xx_handle_irq();
is7xx_interrupt_dev_id = NULL;
enable_irq(is7xx_interrupt_irq);
}
} while (!signal_pending(current));
complete_and_exit(&is7xx_exited, 0);
}
/*===========================================================================
===========================================================================*/
static void is7xx_interrupt(int irq, void *dev_id,
struct pt_regs *regs)
{
if(irq == IS7XX_IRQ) {
is7xx_interrupt_dev_id = dev_id;
is7xx_interrupt_irq = irq;
disable_irq(irq);
wake_up(&is7xx_wait);
} else {
printk(KERN_ERR "wrong 16is7-- serial interrupt"
"expected %d got %d\n",IS7XX_IRQ, irq);
}}
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