diff --git a/arch/ia64/kernel/irq_ia64.c b/arch/ia64/kernel/irq_ia64.c
index 6c4d59f..ef9a2b4 100644
--- a/arch/ia64/kernel/irq_ia64.c
+++ b/arch/ia64/kernel/irq_ia64.c
@@ -46,6 +46,10 @@
 
 #define IRQ_DEBUG	0
 
+/* These can be overridden in platform_irq_init */
+int ia64_first_device_vector = IA64_DEF_FIRST_DEVICE_VECTOR;
+int ia64_last_device_vector = IA64_DEF_LAST_DEVICE_VECTOR;
+
 /* default base addr of IPI table */
 void __iomem *ipi_base_addr = ((void __iomem *)
 			       (__IA64_UNCACHED_OFFSET | IA64_IPI_DEFAULT_BASE_ADDR));
@@ -60,7 +64,7 @@
 };
 EXPORT_SYMBOL(isa_irq_to_vector_map);
 
-static unsigned long ia64_vector_mask[BITS_TO_LONGS(IA64_NUM_DEVICE_VECTORS)];
+static unsigned long ia64_vector_mask[BITS_TO_LONGS(IA64_MAX_DEVICE_VECTORS)];
 
 int
 assign_irq_vector (int irq)
@@ -89,6 +93,19 @@
 		printk(KERN_WARNING "%s: double free!\n", __FUNCTION__);
 }
 
+int
+reserve_irq_vector (int vector)
+{
+	int pos;
+
+	if (vector < IA64_FIRST_DEVICE_VECTOR ||
+	    vector > IA64_LAST_DEVICE_VECTOR)
+		return -EINVAL;
+
+	pos = vector - IA64_FIRST_DEVICE_VECTOR;
+	return test_and_set_bit(pos, ia64_vector_mask);
+}
+
 #ifdef CONFIG_SMP
 #	define IS_RESCHEDULE(vec)	(vec == IA64_IPI_RESCHEDULE)
 #else
diff --git a/arch/ia64/sn/kernel/irq.c b/arch/ia64/sn/kernel/irq.c
index c265e02..db187f5 100644
--- a/arch/ia64/sn/kernel/irq.c
+++ b/arch/ia64/sn/kernel/irq.c
@@ -202,6 +202,9 @@
 	int i;
 	irq_desc_t *base_desc = irq_desc;
 
+	ia64_first_device_vector = IA64_SN2_FIRST_DEVICE_VECTOR;
+	ia64_last_device_vector = IA64_SN2_LAST_DEVICE_VECTOR;
+
 	for (i = 0; i < NR_IRQS; i++) {
 		if (base_desc[i].handler == &no_irq_type) {
 			base_desc[i].handler = &irq_type_sn;
@@ -285,6 +288,7 @@
 	/* link it into the sn_irq[irq] list */
 	spin_lock(&sn_irq_info_lock);
 	list_add_rcu(&sn_irq_info->list, sn_irq_lh[sn_irq_info->irq_irq]);
+	reserve_irq_vector(sn_irq_info->irq_irq);
 	spin_unlock(&sn_irq_info_lock);
 
 	register_intr_pda(sn_irq_info);
@@ -310,8 +314,11 @@
 	spin_lock(&sn_irq_info_lock);
 	list_del_rcu(&sn_irq_info->list);
 	spin_unlock(&sn_irq_info_lock);
+	if (list_empty(sn_irq_lh[sn_irq_info->irq_irq]))
+		free_irq_vector(sn_irq_info->irq_irq);
 	call_rcu(&sn_irq_info->rcu, sn_irq_info_free);
 	pci_dev_put(pci_dev);
+
 }
 
 static inline void
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 55ff52d..f810578 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -35,7 +35,7 @@
 
 #ifndef CONFIG_X86_IO_APIC
 int vector_irq[NR_VECTORS] = { [0 ... NR_VECTORS - 1] = -1};
-u8 irq_vector[NR_IRQ_VECTORS] = { FIRST_DEVICE_VECTOR , 0 };
+u8 irq_vector[NR_IRQ_VECTORS];
 #endif
 
 static struct msi_ops *msi_ops;
@@ -383,6 +383,10 @@
 		return status;
 	}
 
+#ifndef CONFIG_X86_IO_APIC
+	irq_vector[0] = FIRST_DEVICE_VECTOR;
+#endif
+
 	if (last_alloc_vector < 0) {
 		pci_msi_enable = 0;
 		printk(KERN_WARNING "PCI: No interrupt vectors available for MSI\n");
diff --git a/include/asm-ia64/hw_irq.h b/include/asm-ia64/hw_irq.h
index 0cf119b..ea8b8c4 100644
--- a/include/asm-ia64/hw_irq.h
+++ b/include/asm-ia64/hw_irq.h
@@ -47,9 +47,19 @@
 #define IA64_CMC_VECTOR			0x1f	/* corrected machine-check interrupt vector */
 /*
  * Vectors 0x20-0x2f are reserved for legacy ISA IRQs.
+ * Use vectors 0x30-0xe7 as the default device vector range for ia64.
+ * Platforms may choose to reduce this range in platform_irq_setup, but the
+ * platform range must fall within
+ *	[IA64_DEF_FIRST_DEVICE_VECTOR..IA64_DEF_LAST_DEVICE_VECTOR]
  */
-#define IA64_FIRST_DEVICE_VECTOR	0x30
-#define IA64_LAST_DEVICE_VECTOR		0xe7
+extern int ia64_first_device_vector;
+extern int ia64_last_device_vector;
+
+#define IA64_DEF_FIRST_DEVICE_VECTOR	0x30
+#define IA64_DEF_LAST_DEVICE_VECTOR	0xe7
+#define IA64_FIRST_DEVICE_VECTOR	ia64_first_device_vector
+#define IA64_LAST_DEVICE_VECTOR		ia64_last_device_vector
+#define IA64_MAX_DEVICE_VECTORS		(IA64_DEF_LAST_DEVICE_VECTOR - IA64_DEF_FIRST_DEVICE_VECTOR + 1)
 #define IA64_NUM_DEVICE_VECTORS		(IA64_LAST_DEVICE_VECTOR - IA64_FIRST_DEVICE_VECTOR + 1)
 
 #define IA64_MCA_RENDEZ_VECTOR		0xe8	/* MCA rendez interrupt */
@@ -83,6 +93,7 @@
 
 extern int assign_irq_vector (int irq);	/* allocate a free vector */
 extern void free_irq_vector (int vector);
+extern int reserve_irq_vector (int vector);
 extern void ia64_send_ipi (int cpu, int vector, int delivery_mode, int redirect);
 extern void register_percpu_irq (ia64_vector vec, struct irqaction *action);