ec_set_irq_priority
ret = ec_set_irq_priority(irqno, ipl);
err = ec_set_irq_priority(irqno, max_ipl);
err = ec_set_irq_priority(hdlp->ih_vector, new_priority);
ret = ec_set_irq_priority(irqno, ipl);
err = ec_set_irq_priority(irqno, max_ipl);
extern int ec_set_irq_priority(int, int);