[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>

1 files changed, 3 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d25acd51e181..733a736bc6c8 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -104,6 +104,9 @@ loader, and have no meaning to the kernel directly.
 Do not modify the syntax of boot loader parameters without extreme
 need or coordination with <Documentation/i386/boot.txt>.
 
+There are also arch-specific kernel-parameters not documented here.
+See for example <Documentation/x86_64/boot-options.txt>.
+
 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
 a trailing = on the name of any parameter states that that parameter will
 be entered as an environment variable, whereas its absence indicates that