+#ifdef CONFIG_ACPI_DEALLOCATE_IRQ
+void
+iosapic_unregister_intr (unsigned int gsi)
+{
+ unsigned long flags;
+ int irq, vector;
+ irq_desc_t *idesc;
+ int rte_index;
+ unsigned long trigger, polarity;
+
+ /*
+ * If the irq associated with the gsi is not found,
+ * iosapic_unregister_intr() is unbalanced. We need to check
+ * this again after getting locks.
+ */
+ irq = gsi_to_irq(gsi);
+ if (irq < 0) {
+ printk(KERN_ERR "iosapic_unregister_intr(%u) unbalanced\n", gsi);
+ WARN_ON(1);
+ return;
+ }
+ vector = irq_to_vector(irq);
+
+ idesc = irq_descp(irq);
+ spin_lock_irqsave(&idesc->lock, flags);
+ spin_lock(&iosapic_lock);
+ {
+ rte_index = iosapic_intr_info[vector].rte_index;
+ if (rte_index < 0) {
+ spin_unlock(&iosapic_lock);
+ spin_unlock_irqrestore(&idesc->lock, flags);
+ printk(KERN_ERR "iosapic_unregister_intr(%u) unbalanced\n", gsi);
+ WARN_ON(1);
+ return;
+ }
+
+ if (--iosapic_intr_info[vector].refcnt > 0) {
+ spin_unlock(&iosapic_lock);
+ spin_unlock_irqrestore(&idesc->lock, flags);
+ return;
+ }
+
+ /*
+ * If interrupt handlers still exist on the irq
+ * associated with the gsi, don't unregister the
+ * interrupt.
+ */
+ if (idesc->action) {
+ iosapic_intr_info[vector].refcnt++;
+ spin_unlock(&iosapic_lock);
+ spin_unlock_irqrestore(&idesc->lock, flags);
+ printk(KERN_WARNING "Cannot unregister GSI. IRQ %u is still in use.\n", irq);
+ return;
+ }
+
+ /* Clear the interrupt controller descriptor. */
+ idesc->handler = &no_irq_type;
+
+ trigger = iosapic_intr_info[vector].trigger;
+ polarity = iosapic_intr_info[vector].polarity;
+
+ /* Clear the interrupt information. */
+ memset(&iosapic_intr_info[vector], 0, sizeof(struct iosapic_intr_info));
+ iosapic_intr_info[vector].rte_index = -1; /* mark as unused */
+ }
+ spin_unlock(&iosapic_lock);
+ spin_unlock_irqrestore(&idesc->lock, flags);
+
+ /* Free the interrupt vector */
+ free_irq_vector(vector);
+
+ printk(KERN_INFO "GSI %u (%s, %s) -> vector %d unregisterd.\n",
+ gsi, (trigger == IOSAPIC_EDGE ? "edge" : "level"),
+ (polarity == IOSAPIC_POL_HIGH ? "high" : "low"),
+ vector);
+}
+#endif /* CONFIG_ACPI_DEALLOCATE_IRQ */
+