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 c9d2b81..7081958 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -760,15 +760,21 @@
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"