GART IOMMU support

modulename: pci-gart_64.ko

and/or

amd_gart_64.ko

configname: CONFIG_GART_IOMMU

Linux Kernel Configuration for x86
└─>Processor type and features
└─>GART IOMMU support
In linux kernel since version 2.6.12  
Support for full DMA access of devices with 32bit memory access only
on systems with more than 3GB. This is usually needed for USB,
sound, many IDE/SATA chipsets and some other devices.
Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
based hardware IOMMU and a software bounce buffer based IOMMU used
on Intel systems and as fallback.
The code is only active when needed (enough memory and limited
device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
too.

source code: