IOMMU support

modulename: pci-gart.ko

configname: CONFIG_GART_IOMMU

Linux Kernel Configuration
└─>Processor type and features
└─>IOMMU support
In linux kernel since version 2.6.12  
Support the IOMMU. Needed to run systems with more than 3GB of memory
properly with 32-bit PCI devices that do not support DAC (Double Address
Cycle). The IOMMU can be turned off at runtime with the iommu=off parameter.
Normally the kernel will take the right choice by itself.
This option includes a driver for the AMD Opteron/Athlon64 IOMMU
and a software emulation used on some other systems.
If unsure, say Y.

source code:
selects

CONFIG_SWIOTLB

depends
CONFIG_PCI