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authorJoerg Roedel <joerg.roedel@amd.com>2010-05-31 15:05:20 +0200
committerJoerg Roedel <joerg.roedel@amd.com>2010-06-01 10:20:15 +0200
commitd7f0776975334070a93370ae048fda0c31a91c38 (patch)
treee1eb9681756be538f8108a1b1fd54f8b1eb0e294 /arch/x86
parente82752d8b5a7e0a5e4d607fd8713549e2a4e2741 (diff)
x86/amd-iommu: Fall back to GART if initialization fails
This patch implements a fallback to the GART IOMMU if this is possible and the AMD IOMMU initialization failed. Otherwise the fallback would be nommu which is very problematic on machines with more than 4GB of memory or swiotlb which hurts io-performance. Cc: stable@kernel.org Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/amd_iommu.c4
-rw-r--r--arch/x86/kernel/amd_iommu_init.c9
2 files changed, 9 insertions, 4 deletions
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 8a9aaa8412c..0d20286d78c 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2330,10 +2330,6 @@ int __init amd_iommu_init_dma_ops(void)
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;
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 1405346c62b..3cc63e2b8dd 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -1358,6 +1358,15 @@ free:
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;
}