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Altera_Forum
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21 years ago

requsting interrupt fails

Hello,

I have an UL with one interrupt. When I try to request the interrupt, it fails. Here is the code of my driver: 

static int __init mod_init(void)
{
    u8 errorcode;
    printk("DSP: Driver loaded\n");
    if( register_chrdev(240, "DSPDriver", &fops) == 0) {
  printk("DSP: registering device\n");
  if( request_irq(IRQ_NR, driver_isr, SA_INTERRUPT|SA_SHIRQ, "dsp", &fops))
  {
      printk("DSP: Got IRQ %i\n", IRQ_NR);
      return 0;
  }
  else
  {
      printk("DSP: ERROR IRQ request failed!\n");
      
      unregister_chrdev(240, "DSPDriver");
      return -EBUSY;
  }
    }
    printk("DSP: registering device FAILED\n");
    return -EIO;
}
static void __exit mod_exit(void)
{
    printk("cleanup_module called\n");
    free_irq( IRQ_NR, &fops );
    unregister_chrdev(240, "DSPDriver");
}
module_init( mod_init );
module_exit( mod_exit );

I don't know why. My driver should be the only one requesting this IRQ. It doesn't matter if I request it shared or exclusively.

/proc/interrupts looks like this: 

# cat /proc/interrupts
  1:        519   jtag_uart
  3:      90384 L timer
  6:        270   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90386 L timer
  6:        270   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90394 L timer
  6:        274   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90407 L timer
  6:        298   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90420 L timer
  6:        330   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90432 L timer
  6:        330   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90446 L timer
  6:        377   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90458 L timer
  6:        383   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90471 L timer
  6:        403   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90484 L timer
  6:        421   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90497 L timer
  6:        455   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90511 L timer
  6:        527   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90516 L timer
  6:        527   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90527 L timer
  6:        535   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90531 L timer
  6:        535   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90533 L timer
  6:        535   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90534 L timer
  6:        538   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90535 L timer
  6:        538   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90536 L timer
  6:        538   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90550 L timer
  6:        571   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90553 L timer
  6:        571   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90554 L timer
  6:        571   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90555 L timer
  6:        571   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90556 L timer
  6:        571   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90567 L timer
  6:        579   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90570 L timer
  6:        579   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90571 L timer
  6:        580   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90572 L timer
  6:        580   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90573 L timer
  6:        580   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90575 L timer
  6:        580   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90576 L timer
  6:        580   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90583 L timer
  6:        609   eth0
  8:          0   dsp
   :          0   spurious
  1:        519   jtag_uart
  3:      90589 L timer
  6:        625   eth0
  8:          0   dsp
   :          0   spurious

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    > When I try to request the interrupt, it fails.

    Based on /proc/interrupts, request_irq() did not fail and

    assigned you interrupt number 8.

    --Scott
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    But why do I always get 

    DSP: Driver loaded
DSP: registering device
DSP: ERROR IRQ request failed!

    when I load the driver?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    Hi MRKs,

    The value returned from request_irq() is either 0 to indicate success

    or a negative error code ... just test for zero & you should be fine:

    if( request_irq(IRQ_NR, driver_isr, SA_INTERRUPT|SA_SHIRQ, "dsp", &fops) == 0)

    or test for zero

    Regards,

    --Scott