IORESOURCE_IRQ_OPTIONAL
if (irq->flags & IORESOURCE_IRQ_OPTIONAL)
if (rule->flags & IORESOURCE_IRQ_OPTIONAL) {
irq->flags |= IORESOURCE_IRQ_OPTIONAL;
irq->flags |= IORESOURCE_IRQ_OPTIONAL;
if (irq->flags & IORESOURCE_IRQ_OPTIONAL)