Index: sys/arm/mv/mv_ap806_gicp.c
===================================================================
--- sys/arm/mv/mv_ap806_gicp.c
+++ sys/arm/mv/mv_ap806_gicp.c
@@ -395,8 +395,8 @@
 
 	for (i = 0; i < count; i++) {
 		BIT_SET(sc->msi_bitmap_size,
-		    mv_ap806_gicp_irq_to_msi(sc, srcs[i]->isrc_irq),
-		    sc->msi_bitmap);
+		    mv_ap806_gicp_irq_to_msi(sc,
+		    rman_get_start(srcs[i]->isrc_irq)), sc->msi_bitmap);
 	}
 
 	return (0);
@@ -411,7 +411,7 @@
 	sc = device_get_softc(dev);
 
 	*addr = rman_get_start(sc->res);
-	*data = mv_ap806_gicp_irq_to_msi(sc, isrc->isrc_irq);
+	*data = mv_ap806_gicp_irq_to_msi(sc, rman_get_start(isrc->isrc_irq));
 
 	return (0);
 }
Index: sys/arm/mv/mv_ap806_sei.c
===================================================================
--- sys/arm/mv/mv_ap806_sei.c
+++ sys/arm/mv/mv_ap806_sei.c
@@ -453,7 +453,7 @@
 
 	for (i = 0; i < count; i++) {
 		BIT_SET(MV_AP806_SEI_CP_SIZE,
-		    srcs[i]->isrc_irq - MV_AP806_SEI_CP_FIRST,
+		    rman_get_start(srcs[i]->isrc_irq) - MV_AP806_SEI_CP_FIRST,
 		    &sc->msi_bitmap);
 	}
 
@@ -469,7 +469,7 @@
 	sc = device_get_softc(dev);
 
 	*addr = rman_get_start(sc->mem_res) + MV_AP806_SEI_SETSPI_OFFSET;
-	*data = isrc->isrc_irq;
+	*data = rman_get_start(isrc->isrc_irq);
 
 	return (0);
 }
Index: sys/kern/subr_intr.c
===================================================================
--- sys/kern/subr_intr.c
+++ sys/kern/subr_intr.c
@@ -133,7 +133,7 @@
 /* Interrupt source definition. */
 static struct mtx isrc_table_lock;
 static struct intr_irqsrc **irq_sources;
-u_int irq_next_free;
+static struct rman intr_avail;
 
 #ifdef SMP
 #ifdef EARLY_AP_STARTUP
@@ -190,6 +190,14 @@
 	sintrnames = intrcnt_count * INTRNAME_LEN;
 	irq_sources = mallocarray(intr_nirq, sizeof(struct intr_irqsrc*),
 	    M_INTRNG, M_WAITOK | M_ZERO);
+
+	intr_avail.rm_start = 0;
+	intr_avail.rm_end = intr_nirq - 1;
+	intr_avail.rm_type = RMAN_ARRAY;
+	intr_avail.rm_descr = "INTRNG available interrupts";
+	if (rman_init(&intr_avail) ||
+	    rman_manage_region(&intr_avail, 0, intr_nirq - 1))
+		panic("%s(): failure initializing free rman", __func__);
 }
 SYSINIT(intr_irq_init, SI_SUB_INTR, SI_ORDER_FIRST, intr_irq_init, NULL);
 
@@ -401,32 +409,20 @@
 static inline int
 isrc_alloc_irq(struct intr_irqsrc *isrc)
 {
-	u_int irq;
+	struct resource *irq;
 
 	mtx_assert(&isrc_table_lock, MA_OWNED);
 
-	if (irq_next_free >= intr_nirq)
-		return (ENOSPC);
-
-	for (irq = irq_next_free; irq < intr_nirq; irq++) {
-		if (irq_sources[irq] == NULL)
-			goto found;
-	}
-	for (irq = 0; irq < irq_next_free; irq++) {
-		if (irq_sources[irq] == NULL)
-			goto found;
-	}
+	irq = rman_reserve_resource(&intr_avail, 0, ~0, 1,
+	    RF_ACTIVE | RF_UNMAPPED, isrc->isrc_dev);
 
-	irq_next_free = intr_nirq;
-	return (ENOSPC);
+	if (irq == NULL)
+		return (ENOSPC);
 
-found:
 	isrc->isrc_irq = irq;
-	irq_sources[irq] = isrc;
 
-	irq_next_free = irq + 1;
-	if (irq_next_free >= intr_nirq)
-		irq_next_free = 0;
+	irq_sources[rman_get_start(irq)] = isrc;
+
 	return (0);
 }
 
@@ -439,22 +435,21 @@
 
 	mtx_assert(&isrc_table_lock, MA_OWNED);
 
-	if (isrc->isrc_irq >= intr_nirq)
+	if (isrc->isrc_irq == NULL)
+		return (EINVAL);
+	KASSERT(rman_is_region_manager(isrc->isrc_irq, &intr_avail),
+	    ("%s(): intr_irqsrc with invalid irq (not region manager)",
+	    __func__));
+	if (rman_get_start(isrc->isrc_irq) >= intr_nirq)
 		return (EINVAL);
-	if (irq_sources[isrc->isrc_irq] != isrc)
+	if (irq_sources[rman_get_start(isrc->isrc_irq)] != isrc)
 		return (EINVAL);
 
-	irq_sources[isrc->isrc_irq] = NULL;
-	isrc->isrc_irq = INTR_IRQ_INVALID;	/* just to be safe */
+	irq_sources[rman_get_start(isrc->isrc_irq)] = NULL;
 
-	/*
-	 * If we are recovering from the state irq_sources table is full,
-	 * then the following allocation should check the entire table. This
-	 * will ensure maximum separation of allocation order from release
-	 * order.
-	 */
-	if (irq_next_free >= intr_nirq)
-		irq_next_free = 0;
+	rman_release_resource(isrc->isrc_irq);
+
+	isrc->isrc_irq = NULL;	/* just to be safe */
 
 	return (0);
 }
@@ -471,7 +466,7 @@
 
 	bzero(isrc, sizeof(struct intr_irqsrc));
 	isrc->isrc_dev = dev;
-	isrc->isrc_irq = INTR_IRQ_INVALID;	/* just to be safe */
+	isrc->isrc_irq = NULL;	/* just to be safe */
 	isrc->isrc_flags = flags;
 
 	va_start(ap, fmt);
@@ -650,7 +645,7 @@
 	struct intr_event *ie;
 	int error;
 
-	error = intr_event_create(&ie, isrc, 0, isrc->isrc_irq,
+	error = intr_event_create(&ie, isrc, 0, rman_get_start(isrc->isrc_irq),
 	    intr_isrc_pre_ithread, intr_isrc_post_ithread, intr_isrc_post_filter,
 	    intr_isrc_assign_cpu, "%s:", isrc->isrc_name);
 	if (error)
@@ -1078,14 +1073,15 @@
 	if (flags & INTR_SOLO) {
 		error = iscr_setup_filter(isrc, name, (intr_irq_filter_t *)filt,
 		    arg, cookiep);
-		debugf("irq %u setup filter error %d on %s\n", isrc->isrc_irq, error,
-		    name);
+		debugf("irq %u setup filter error %d on %s\n",
+		    rman_get_start(isrc->isrc_irq), error, name);
 	} else
 #endif
 		{
 		error = isrc_add_handler(isrc, name, filt, hand, arg, flags,
 		    cookiep);
-		debugf("irq %u add handler error %d on %s\n", isrc->isrc_irq, error, name);
+		debugf("irq %u add handler error %d on %s\n",
+		    rman_get_start(isrc->isrc_irq), error, name);
 	}
 	if (error != 0)
 		return (error);
Index: sys/sys/intr.h
===================================================================
--- sys/sys/intr.h
+++ sys/sys/intr.h
@@ -82,7 +82,7 @@
 /* Interrupt source definition. */
 struct intr_irqsrc {
 	device_t		isrc_dev;	/* where isrc is mapped */
-	u_int			isrc_irq;	/* unique identificator */
+	struct resource		*isrc_irq;	/* unique identificator */
 	u_int			isrc_flags;
 	char			isrc_name[INTR_ISRC_NAMELEN];
 	cpuset_t		isrc_cpu;	/* on which CPUs is enabled */