diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index af0e939..309c47b 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -282,6 +282,13 @@
 	out-of-tree driver.
 Who:	Thomas Gleixner <tglx@linutronix.de>
 
+----------------------------
+
+What:	usedac i386 kernel parameter
+When:	2.6.27
+Why:	replaced by allowdac and no dac combination
+Who:	Glauber Costa <gcosta@redhat.com>
+
 ---------------------------
 
 What:	/sys/o2cb symlink
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 7d3bd65..48ab52d 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -24,6 +24,18 @@
 int force_iommu __read_mostly = 0;
 #endif
 
+int iommu_merge __read_mostly = 0;
+
+int no_iommu __read_mostly;
+/* Set this to 1 if there is a HW IOMMU in the system */
+int iommu_detected __read_mostly = 0;
+
+/* This tells the BIO block layer to assume merging. Default to off
+   because we cannot guarantee merging later. */
+int iommu_bio_merge __read_mostly = 0;
+EXPORT_SYMBOL(iommu_bio_merge);
+
+
 int dma_set_mask(struct device *dev, u64 mask)
 {
 	if (!dev->dma_mask || !dma_supported(dev, mask))
@@ -105,6 +117,75 @@
 }
 #endif
 
+/*
+ * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
+ * documentation.
+ */
+static __init int iommu_setup(char *p)
+{
+	iommu_merge = 1;
+
+	if (!p)
+		return -EINVAL;
+
+	while (*p) {
+		if (!strncmp(p, "off", 3))
+			no_iommu = 1;
+		/* gart_parse_options has more force support */
+		if (!strncmp(p, "force", 5))
+			force_iommu = 1;
+		if (!strncmp(p, "noforce", 7)) {
+			iommu_merge = 0;
+			force_iommu = 0;
+		}
+
+		if (!strncmp(p, "biomerge", 8)) {
+			iommu_bio_merge = 4096;
+			iommu_merge = 1;
+			force_iommu = 1;
+		}
+		if (!strncmp(p, "panic", 5))
+			panic_on_overflow = 1;
+		if (!strncmp(p, "nopanic", 7))
+			panic_on_overflow = 0;
+		if (!strncmp(p, "merge", 5)) {
+			iommu_merge = 1;
+			force_iommu = 1;
+		}
+		if (!strncmp(p, "nomerge", 7))
+			iommu_merge = 0;
+		if (!strncmp(p, "forcesac", 8))
+			iommu_sac_force = 1;
+		if (!strncmp(p, "allowdac", 8))
+			forbid_dac = 0;
+		if (!strncmp(p, "nodac", 5))
+			forbid_dac = -1;
+		if (!strncmp(p, "usedac", 6)) {
+			forbid_dac = -1;
+			return 1;
+		}
+#ifdef CONFIG_SWIOTLB
+		if (!strncmp(p, "soft", 4))
+			swiotlb = 1;
+#endif
+
+#ifdef CONFIG_GART_IOMMU
+		gart_parse_options(p);
+#endif
+
+#ifdef CONFIG_CALGARY_IOMMU
+		if (!strncmp(p, "calgary", 7))
+			use_calgary = 1;
+#endif /* CONFIG_CALGARY_IOMMU */
+
+		p += strcspn(p, ",");
+		if (*p == ',')
+			++p;
+	}
+	return 0;
+}
+early_param("iommu", iommu_setup);
+
 int dma_supported(struct device *dev, u64 mask)
 {
 #ifdef CONFIG_PCI
diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index 1d4091a..eea52df 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -153,15 +153,3 @@
 	return mem->virt_base + (pos << PAGE_SHIFT);
 }
 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
-
-#ifdef CONFIG_PCI
-static int check_iommu(char *s)
-{
-	if (!strcmp(s, "usedac")) {
-		forbid_dac = -1;
-		return 1;
-	}
-	return 0;
-}
-__setup("iommu=", check_iommu);
-#endif
diff --git a/arch/x86/kernel/pci-dma_64.c b/arch/x86/kernel/pci-dma_64.c
index c80da76..e7d45cf 100644
--- a/arch/x86/kernel/pci-dma_64.c
+++ b/arch/x86/kernel/pci-dma_64.c
@@ -14,22 +14,9 @@
 #include <asm/gart.h>
 #include <asm/calgary.h>
 
-int iommu_merge __read_mostly = 0;
-
 dma_addr_t bad_dma_address __read_mostly;
 EXPORT_SYMBOL(bad_dma_address);
 
-/* This tells the BIO block layer to assume merging. Default to off
-   because we cannot guarantee merging later. */
-int iommu_bio_merge __read_mostly = 0;
-EXPORT_SYMBOL(iommu_bio_merge);
-
-extern int iommu_sac_force;
-
-int no_iommu __read_mostly;
-/* Set this to 1 if there is a HW IOMMU in the system */
-int iommu_detected __read_mostly = 0;
-
 /* Dummy device used for NULL arguments (normally ISA). Better would
    be probably a smaller DMA mask, but this is bug-to-bug compatible
    to i386. */
@@ -160,69 +147,3 @@
 	free_pages((unsigned long)vaddr, get_order(size));
 }
 EXPORT_SYMBOL(dma_free_coherent);
-
-/*
- * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
- * documentation.
- */
-static __init int iommu_setup(char *p)
-{
-	iommu_merge = 1;
-
-	if (!p)
-		return -EINVAL;
-
-	while (*p) {
-		if (!strncmp(p, "off", 3))
-			no_iommu = 1;
-		/* gart_parse_options has more force support */
-		if (!strncmp(p, "force", 5))
-			force_iommu = 1;
-		if (!strncmp(p, "noforce", 7)) {
-			iommu_merge = 0;
-			force_iommu = 0;
-		}
-
-		if (!strncmp(p, "biomerge", 8)) {
-			iommu_bio_merge = 4096;
-			iommu_merge = 1;
-			force_iommu = 1;
-		}
-		if (!strncmp(p, "panic", 5))
-			panic_on_overflow = 1;
-		if (!strncmp(p, "nopanic", 7))
-			panic_on_overflow = 0;
-		if (!strncmp(p, "merge", 5)) {
-			iommu_merge = 1;
-			force_iommu = 1;
-		}
-		if (!strncmp(p, "nomerge", 7))
-			iommu_merge = 0;
-		if (!strncmp(p, "forcesac", 8))
-			iommu_sac_force = 1;
-		if (!strncmp(p, "allowdac", 8))
-			forbid_dac = 0;
-		if (!strncmp(p, "nodac", 5))
-			forbid_dac = -1;
-
-#ifdef CONFIG_SWIOTLB
-		if (!strncmp(p, "soft", 4))
-			swiotlb = 1;
-#endif
-
-#ifdef CONFIG_GART_IOMMU
-		gart_parse_options(p);
-#endif
-
-#ifdef CONFIG_CALGARY_IOMMU
-		if (!strncmp(p, "calgary", 7))
-			use_calgary = 1;
-#endif /* CONFIG_CALGARY_IOMMU */
-
-		p += strcspn(p, ",");
-		if (*p == ',')
-			++p;
-	}
-	return 0;
-}
-early_param("iommu", iommu_setup);
diff --git a/include/asm-x86/dma-mapping.h b/include/asm-x86/dma-mapping.h
index d82517d..7580736 100644
--- a/include/asm-x86/dma-mapping.h
+++ b/include/asm-x86/dma-mapping.h
@@ -15,6 +15,7 @@
 extern struct device fallback_dev;
 extern int panic_on_overflow;
 extern int forbid_dac;
+extern int force_iommu;
 
 struct dma_mapping_ops {
 	int             (*mapping_error)(dma_addr_t dma_addr);