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

Steven Scholz steven.scholz at
Wed Apr 14 00:08:24 EST 2004

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-> = 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


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

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