diff --git a/arch/x86/kernel/pci-dma_64.c b/arch/x86/kernel/pci-dma_64.c
index aa805b11b24fe627d0677cdce90c11ba7afbb4d6..5552d23d23c27558ec32f64930f14f6870181ba5 100644
--- a/arch/x86/kernel/pci-dma_64.c
+++ b/arch/x86/kernel/pci-dma_64.c
@@ -12,7 +12,7 @@
 #include <asm/gart.h>
 #include <asm/calgary.h>
 
-int iommu_merge __read_mostly = 1;
+int iommu_merge __read_mostly = 0;
 EXPORT_SYMBOL(iommu_merge);
 
 dma_addr_t bad_dma_address __read_mostly;