Merge branch 'amd-iommu/2.6.35' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu into x86/urgent

arch/x86/kernel/amd_iommu.c

···
 			   struct protection_domain *domain)
 {
 	struct iommu_dev_data *dev_data, *alias_data;
+	int ret;
 
 	dev_data   = get_dev_data(dev);
 	alias_data = get_dev_data(dev_data->alias);
···
 	spin_lock(&domain->lock);
 
 	/* Some sanity checks */
+	ret = -EBUSY;
 	if (alias_data->domain != NULL &&
 	    alias_data->domain != domain)
-		return -EBUSY;
+		goto out_unlock;
 
 	if (dev_data->domain != NULL &&
 	    dev_data->domain != domain)
-		return -EBUSY;
+		goto out_unlock;
 
 	/* Do real assignment */
 	if (dev_data->alias != dev) {
···
 
 	atomic_inc(&dev_data->bind);
 
+	ret = 0;
+
+out_unlock:
+
 	/* ready */
 	spin_unlock(&domain->lock);
 
-	return 0;
+	return ret;
 }
 
 /*
···
 
 	iommu_detected = 1;
 	swiotlb = 0;
-#ifdef CONFIG_GART_IOMMU
-	gart_iommu_aperture_disabled = 1;
-	gart_iommu_aperture = 0;
-#endif
 
 	/* Make the driver finally visible to the drivers */
 	dma_ops = &amd_iommu_dma_ops;

arch/x86/kernel/amd_iommu_init.c

···
 {
 	u8 *ret;
 
-	if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu"))
+	if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu")) {
+		pr_err("AMD-Vi: Can not reserve memory region %llx for mmio\n",
+			address);
+		pr_err("AMD-Vi: This is a BIOS bug. Please contact your hardware vendor\n");
 		return NULL;
+	}
 
 	ret = ioremap_nocache(address, MMIO_REGION_LENGTH);
 	if (ret != NULL)
···
 		ret = amd_iommu_init_dma_ops();
 
 	if (ret)
-		goto free;
+		goto free_disable;
 
 	amd_iommu_init_api();
 
···
 out:
 	return ret;
 
-free:
+free_disable:
 	disable_iommus();
 
+free:
 	amd_iommu_uninit_devices();
 
 	free_pages((unsigned long)amd_iommu_pd_alloc_bitmap,
···
 	free_iommu_all();
 
 	free_unity_maps();
+
+#ifdef CONFIG_GART_IOMMU
+	/*
+	 * We failed to initialize the AMD IOMMU - try fallback to GART
+	 * if possible.
+	 */
+	gart_iommu_init();
+
+#endif
 
 	goto out;
 }