noop_handler
ret = request_irq(virq, noop_handler, 0, "test_irq", NULL);
ret = request_irq(virq, noop_handler, 0, "test_irq", NULL);
ret = request_irq(virq, noop_handler, 0, "test_irq", NULL);
ret = request_irq(virq, noop_handler, 0, "test_irq", NULL);
ret = request_irq(virq, noop_handler, 0, "test_irq", NULL);