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>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c9d2b81ea310795d089474f28624e13202605030..7081958a32fb202348e0fa05fba84663ce76d9d8 100644 (file)
--- 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"