x86/iommu: Clean up the CONFIG_GART_IOMMU config option a bit

Improve the explanation of this config option.

Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/n/tip-gUMmysvsbl3mccbyf6olmxqg@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 15 insertions, 9 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c9d2b81ea310..7081958a32fb 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -760,15 +760,21 @@ config GART_IOMMU
         select SWIOTLB
         depends on X86_64 && PCI && AMD_NB
         ---help---
-          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 older AMD Athlon64/Opteron/Turion/Sempron GART
-          based hardware IOMMU.
-          Newer systems typically have a better AMD IOMMU.
-          The code is only active when needed (enough memory and limited
-          device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
-          too.
+          Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
+          GART based hardware IOMMUs.
+
+          The GART supports full DMA access for devices with 32-bit access
+          limitations, on systems with more than 3 GB. This is usually needed
+          for USB, sound, many IDE/SATA chipsets and some other devices.
+
+          Newer systems typically have a modern AMD IOMMU, supported via
+          the CONFIG_AMD_IOMMU=y config option.
+
+          In normal configurations this driver is only active when needed:
+          there's more than 3 GB of memory and the system contains a
+          32-bit limited device.
+
+          If unsure, say Y.
 
 config CALGARY_IOMMU
         bool "IBM Calgary IOMMU support"