Index: head/sys/dev/iommu/busdma_iommu.c
===================================================================
--- head/sys/dev/iommu/busdma_iommu.c
+++ head/sys/dev/iommu/busdma_iommu.c
@@ -888,7 +888,7 @@
 	struct bus_dmamap_iommu *map;
 	struct iommu_ctx *ctx;
 	struct iommu_domain *domain;
-#if defined(__amd64__)
+#ifndef IOMMU_DOMAIN_UNLOAD_SLEEP
 	struct iommu_map_entries_tailq entries;
 #endif
 
@@ -898,13 +898,13 @@
 	domain = ctx->domain;
 	atomic_add_long(&ctx->unloads, 1);
 
-#if defined(__i386__)
+#if defined(IOMMU_DOMAIN_UNLOAD_SLEEP)
 	IOMMU_DOMAIN_LOCK(domain);
 	TAILQ_CONCAT(&domain->unload_entries, &map->map_entries, dmamap_link);
 	IOMMU_DOMAIN_UNLOCK(domain);
 	taskqueue_enqueue(domain->iommu->delayed_taskqueue,
 	    &domain->unload_task);
-#else /* defined(__amd64__) */
+#else
 	TAILQ_INIT(&entries);
 	IOMMU_DOMAIN_LOCK(domain);
 	TAILQ_CONCAT(&entries, &map->map_entries, dmamap_link);
Index: head/sys/i386/include/iommu.h
===================================================================
--- head/sys/i386/include/iommu.h
+++ head/sys/i386/include/iommu.h
@@ -4,3 +4,5 @@
 /* $FreeBSD$ */
 
 #include <x86/iommu.h>
+
+#define	IOMMU_DOMAIN_UNLOAD_SLEEP