Index: sys/dev/ahci/ahci_pci.c
===================================================================
--- sys/dev/ahci/ahci_pci.c
+++ sys/dev/ahci/ahci_pci.c
@@ -27,8 +27,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_iommu.h"
-
 #include <sys/param.h>
 #include <sys/module.h>
 #include <sys/systm.h>
@@ -501,7 +499,6 @@
 		i++;
 	ctlr->quirks = ahci_ids[i].quirks;
 
-#ifdef IOMMU
 	if (ctlr->quirks & AHCI_Q_IOMMU_BUSWIDE) {
 		/*
 		 * The controller issues DMA requests from PCI function 1,
@@ -510,7 +507,6 @@
 		 */
 		bus_dma_iommu_set_buswide(dev);
 	}
-#endif
 
 	/* Limit speed for my onboard JMicron external port.
 	 * It is not eSATA really, limit to SATA 1 */
Index: sys/kern/subr_bus_dma.c
===================================================================
--- sys/kern/subr_bus_dma.c
+++ sys/kern/subr_bus_dma.c
@@ -33,6 +33,7 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_bus.h"
+#include "opt_iommu.h"
 
 #include <sys/param.h>
 #include <sys/conf.h>
@@ -785,3 +786,21 @@
 	return;
 }
 
+#ifndef IOMMU
+bool bus_dma_iommu_set_buswide(device_t dev);
+int bus_dma_iommu_load_ident(bus_dma_tag_t dmat, bus_dmamap_t map,
+    vm_paddr_t start, vm_size_t length, int flags);
+
+bool
+bus_dma_iommu_set_buswide(device_t dev)
+{
+	return (false);
+}
+
+int
+bus_dma_iommu_load_ident(bus_dma_tag_t dmat, bus_dmamap_t map,
+    vm_paddr_t start, vm_size_t length, int flags)
+{
+	return (0);
+}
+#endif
Index: sys/x86/x86/busdma_machdep.c
===================================================================
--- sys/x86/x86/busdma_machdep.c
+++ sys/x86/x86/busdma_machdep.c
@@ -34,7 +34,6 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_acpi.h"
-#include "opt_iommu.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -268,22 +267,3 @@
 	tc = (struct bus_dma_tag_common *)dmat;
 	return (tc->impl->tag_destroy(dmat));
 }
-
-#ifndef IOMMU
-bool bus_dma_iommu_set_buswide(device_t dev);
-int bus_dma_iommu_load_ident(bus_dma_tag_t dmat, bus_dmamap_t map,   
-    vm_paddr_t start, vm_size_t length, int flags);
-
-bool
-bus_dma_iommu_set_buswide(device_t dev)
-{
-	return (false);
-}
-
-int
-bus_dma_iommu_load_ident(bus_dma_tag_t dmat, bus_dmamap_t map,
-    vm_paddr_t start, vm_size_t length, int flags)
-{
-	return (0);
-}
-#endif