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SubjectCannot unlock spinlock... Was: Problem in yenta.c, 2nd edition
Hallo l-k,

On Mon, Nov 05, 2001 at 11:29:00AM +0100, Jan Marek wrote:
> >
> > Try moving the block of code which requests the IRQ down
> > so that it comes after the call to cardbus_register().
>
> yes. I tried move the block, what are you wrote about... Bu the
> last messages, what I got from notebook when I modprobe'd
> yenta_socket is:
>
> Yenta IRQ list 04b8, PCI irq11
> Socket status: 30000010
>
> (this messages is generated in function cardbus_register()).
>
> And kernel freeze as before...

I tryed to trace of function request_irq():

I found, that problem is in this code:

--- function setup_irq() from file arch/i386/kernel/irq.c

/* this was setup_x86_irq but it seems pretty generic */
int setup_irq(unsigned int irq, struct irqaction * new)
{
int shared = 0;
unsigned long flags;
struct irqaction *old, **p;
irq_desc_t *desc = irq_desc + irq;

/*
* Some drivers like serial.c use request_irq() heavily,
* so we have to be careful not to interfere with a
* running system.
*/
if (new->flags & SA_SAMPLE_RANDOM) {
/*
* This function might sleep, we want to call it first,
* outside of the atomic block.
* Yes, this might clear the entropy pool if the wrong
* driver is attempted to be loaded, without actually
* installing a new handler, but is this really a problem,
* only the sysadmin is able to do this.
*/
rand_initialize_irq(irq);
}

/*
* The following block of code has to be executed atomically
*/
spin_lock_irqsave(&desc->lock,flags);
printk("setup_irq: spin_lock_irqsave()\n");
p = &desc->action;
if ((old = *p) != NULL) {
/* Can't share interrupts unless both agree to */
if (!(old->flags & new->flags & SA_SHIRQ)) {
spin_unlock_irqrestore(&desc->lock,flags);
return -EBUSY;
}

/* add new interrupt at end of irq queue */
do {
p = &old->next;
old = *p;
} while (old);
shared = 1;
}

*p = new;

if (!shared) {
desc->depth = 0;
desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING);
desc->handler->startup(irq);
printk("request_irq: desc->handler->startup(irq)\n");
}
spin_unlock_irqrestore(&desc->lock,flags);
printk("request_irq: spin_unlock_irqrestore()\n");

register_irq_proc(irq);
printk("request_irq: register_irq_proc()\n");
return 0;
}
--- end of listing

The last message I got from kernel is:
request_irq: desc->handler->startup(irq)

Then problem is in the spin_unlock_irqrestore()???

Any ideas, recomendations, suggestions?

Sincerely
Jan Marek
--
Ing. Jan Marek
University of South Bohemia
Academic Computer Centre
Phone: +420-38-7772080
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