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| author | Anton Arapov <anton@redhat.com> | 2012-06-08 12:58:00 +0200 |
|---|---|---|
| committer | Anton Arapov <anton@redhat.com> | 2012-06-08 12:58:00 +0200 |
| commit | 6792a3f47a2e42d7164292bf7f1a55cfc4c91652 (patch) | |
| tree | b90c002bfbbeaec92f5d8a2383dcabf6524016f7 /Documentation/DMA-attributes.txt | |
| parent | fe2895d3d55146cac65b273c0f83e2c7e543cd0e (diff) | |
| download | kernel-uprobes-6792a3f47a2e42d7164292bf7f1a55cfc4c91652.tar.gz kernel-uprobes-6792a3f47a2e42d7164292bf7f1a55cfc4c91652.tar.xz kernel-uprobes-6792a3f47a2e42d7164292bf7f1a55cfc4c91652.zip | |
fedora kernel: b920e9b748c595f970bf80ede7832d39f8d567dav3.4.1-2
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'Documentation/DMA-attributes.txt')
| -rw-r--r-- | Documentation/DMA-attributes.txt | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index b768cc0e402..5c72eed8956 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -31,3 +31,21 @@ may be weakly ordered, that is that reads and writes may pass each other. Since it is optional for platforms to implement DMA_ATTR_WEAK_ORDERING, those that do not will simply ignore the attribute and exhibit default behavior. + +DMA_ATTR_WRITE_COMBINE +---------------------- + +DMA_ATTR_WRITE_COMBINE specifies that writes to the mapping may be +buffered to improve performance. + +Since it is optional for platforms to implement DMA_ATTR_WRITE_COMBINE, +those that do not will simply ignore the attribute and exhibit default +behavior. + +DMA_ATTR_NON_CONSISTENT +----------------------- + +DMA_ATTR_NON_CONSISTENT lets the platform to choose to return either +consistent or non-consistent memory as it sees fit. By using this API, +you are guaranteeing to the platform that you have all the correct and +necessary sync points for this memory in the driver. |