diff options
-rw-r--r-- | Documentation/kernel-parameters.txt | 7 | ||||
-rw-r--r-- | drivers/pci/intel-iommu.c | 7 |
2 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 8157417724a8..b2361667839f 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt | |||
@@ -781,6 +781,13 @@ and is between 256 and 4096 characters. It is defined in the file | |||
781 | bypassed by not enabling DMAR with this option. In | 781 | bypassed by not enabling DMAR with this option. In |
782 | this case, gfx device will use physical address for | 782 | this case, gfx device will use physical address for |
783 | DMA. | 783 | DMA. |
784 | forcedac [x86_64] | ||
785 | With this option iommu will not optimize to look | ||
786 | for io virtual address below 32 bit forcing dual | ||
787 | address cycle on pci bus for cards supporting greater | ||
788 | than 32 bit addressing. The default is to look | ||
789 | for translation below 32 bit and if not available | ||
790 | then look in the higher range. | ||
784 | 791 | ||
785 | io7= [HW] IO7 for Marvel based alpha systems | 792 | io7= [HW] IO7 for Marvel based alpha systems |
786 | See comment before marvel_specify_io7 in | 793 | See comment before marvel_specify_io7 in |
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 05630b44dbfc..cb24defdb6d9 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c | |||
@@ -54,6 +54,7 @@ static void domain_remove_dev_info(struct dmar_domain *domain); | |||
54 | 54 | ||
55 | static int dmar_disabled; | 55 | static int dmar_disabled; |
56 | static int __initdata dmar_map_gfx = 1; | 56 | static int __initdata dmar_map_gfx = 1; |
57 | static int dmar_forcedac; | ||
57 | 58 | ||
58 | #define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1)) | 59 | #define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1)) |
59 | static DEFINE_SPINLOCK(device_domain_lock); | 60 | static DEFINE_SPINLOCK(device_domain_lock); |
@@ -71,6 +72,10 @@ static int __init intel_iommu_setup(char *str) | |||
71 | dmar_map_gfx = 0; | 72 | dmar_map_gfx = 0; |
72 | printk(KERN_INFO | 73 | printk(KERN_INFO |
73 | "Intel-IOMMU: disable GFX device mapping\n"); | 74 | "Intel-IOMMU: disable GFX device mapping\n"); |
75 | } else if (!strncmp(str, "forcedac", 8)) { | ||
76 | printk (KERN_INFO | ||
77 | "Intel-IOMMU: Forcing DAC for PCI devices\n"); | ||
78 | dmar_forcedac = 1; | ||
74 | } | 79 | } |
75 | 80 | ||
76 | str += strcspn(str, ","); | 81 | str += strcspn(str, ","); |
@@ -1558,7 +1563,7 @@ static dma_addr_t __intel_map_single(struct device *dev, void *addr, | |||
1558 | 1563 | ||
1559 | start_addr = IOVA_START_ADDR; | 1564 | start_addr = IOVA_START_ADDR; |
1560 | 1565 | ||
1561 | if (pdev->dma_mask <= DMA_32BIT_MASK) { | 1566 | if ((pdev->dma_mask <= DMA_32BIT_MASK) || (dmar_forcedac)) { |
1562 | iova = iommu_alloc_iova(domain, addr, size, start_addr, | 1567 | iova = iommu_alloc_iova(domain, addr, size, start_addr, |
1563 | pdev->dma_mask); | 1568 | pdev->dma_mask); |
1564 | } else { | 1569 | } else { |