problem with queue_task() and mark_bh()...

problem with queue_task() and mark_bh()...

[Steven Scholz]

Hi there,

I have a problem with queue_task() and mark_bh().

In a driver for the wireless HERMES-II chipset I found the code snippets

/* Register the ISR handler information here... */
  lp->task.routine = (void (*)(void *))wl_isr_handler;
  lp->task.data = lp;
  printk("wl_isr_handler is @ %#lx\n", lp->task.routine);

At a later point (namely in the interrupt service rountine this happens:

  /* If we have interrupts pending, then put them on a system task queue.*/
  if( events == HCF_INT_PENDING ) {
	/* Schedule the ISR handler as a bottom-half task in the
	 * tq_immediate queue
	 */
	printk( "Schedule the ISR handler %#lx...\n", lp->task.routine);

	queue_task( &( lp->task ), &tq_immediate );
	mark_bh( IMMEDIATE_BH );
}

The problem is now that the queued task lp->task (i.e. wl_isr_handler) never
get's called! And thus the driver does not work.

If I call the function directly using

	lp->task.routine(lp);

instead of queue_task() and mark_bh() the function wl_isr_handler() gets
called and the driver works.

Any idea why queue_task() and mark_bh() do not work as expected?
How could I debug this problem?
(The two printk's show the same address.)

I am using linuxppc-2.4.25 from DENX CVS.

Thanks a million!!!

--
Steven Scholz

imc Measurement & Control               imc Meßsysteme GmbH
Voltastr. 5                             Voltastr. 5
13355 Berlin                            13355 Berlin
Germany                                 Deutschland

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: problem with queue_task() and mark_bh()...

[Steven Scholz]

Hi,

I wrote:

> I have a problem with queue_task() and mark_bh().
> ...
> At a later point (namely in the interrupt service rountine this happens:
>
>  /* If we have interrupts pending, then put them on a system task queue.*/
>  if( events == HCF_INT_PENDING ) {
>     /* Schedule the ISR handler as a bottom-half task in the
>      * tq_immediate queue
>      */
>     printk( "Schedule the ISR handler %#lx...\n", lp->task.routine);
>
>     queue_task( &( lp->task ), &tq_immediate );
>     mark_bh( IMMEDIATE_BH );
> }
>
> The problem is now that the queued task lp->task (i.e. wl_isr_handler)
> never get's called! And thus the driver does not work.

When I call run_task_queue(&tq_immediate) right after mark_bh(IMMEDIATE_BH)
then it works.

But I though "run_task_queue(&tq_immediate)" gets called by the kernel
(after every timer interrupt)...


--
Steven Scholz

imc Measurement & Control               imc Meßsysteme GmbH
Voltastr. 5                             Voltastr. 5
13355 Berlin                            13355 Berlin
Germany                                 Deutschland

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: problem with queue_task() and mark_bh()...

[Steven Scholz]

Hi,

>>     queue_task( &( lp->task ), &tq_immediate );
>>     mark_bh( IMMEDIATE_BH );

I've put some printks in my kernel.

Now I can see that the task is successfully queued, that mark_bh() is called
and the tasklet_hi_schedule() calls __tasklet_hi_schedule().

But the function immediate_bh() in kernel/timer.c (which should then call
run_task_queue(&tq_immediate)) is never called.

Any ideas?

Steven

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/