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authorKarsten Weiss <K.Weiss@science-computing.de>2007-02-13 13:26:21 +0100
committerAndi Kleen <andi@basil.nowhere.org>2007-02-13 13:26:21 +0100
commit5558870bfbcca10cfc7b13ab866687012ea3c9af (patch)
tree45605429a4fd5eee9b05d5e7c852fa72bfd07a21 /arch/x86_64/Kconfig
parent5809f9d442e9dbb23859e2c37d8c47043f6b5cc9 (diff)
[PATCH] x86-64: improved iommu documentation
- add SWIOTLB config help text - mention Documentation/x86_64/boot-options.txt in Documentation/kernel-parameters.txt - remove the duplication of the iommu kernel parameter documentation. - Better explanation of some of the iommu kernel parameter options. - "32MB<<order" instead of "32MB^order". - Mention the default "order" value. - list the four existing PCI-DMA mapping implementations of arch x86_64 - group the iommu= option keywords by PCI-DMA mapping implementation. - Distinguish iommu= option keywords from number arguments. - Explain the meaning of DAC and SAC. Signed-off-by: Karsten Weiss <knweiss@science-computing.de> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Muli Ben-Yehuda <muli@il.ibm.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
Diffstat (limited to 'arch/x86_64/Kconfig')
-rw-r--r--arch/x86_64/Kconfig10
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 02dd39457bc..a55382a1bb4 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -458,8 +458,8 @@ config IOMMU
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 IOMMU and a software bounce buffer based IOMMU used on Intel
- systems and as fallback.
+ 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.
@@ -496,6 +496,12 @@ config CALGARY_IOMMU_ENABLED_BY_DEFAULT
# need this always selected by IOMMU for the VIA workaround
config SWIOTLB
bool
+ help
+ Support for software bounce buffers used on x86-64 systems
+ which don't have a hardware IOMMU (e.g. the current generation
+ of Intel's x86-64 CPUs). Using this PCI devices which can only
+ access 32-bits of memory can be used on systems with more than
+ 3 GB of memory. If unsure, say Y.
config X86_MCE
bool "Machine check support" if EMBEDDED