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Diffstat (limited to 'Documentation/DMA-attributes.txt')
| -rw-r--r-- | Documentation/DMA-attributes.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index 6d772f84b47..b768cc0e402 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -22,3 +22,12 @@ ready and available in memory. The DMA of the "completion indication" could race with data DMA. Mapping the memory used for completion indications with DMA_ATTR_WRITE_BARRIER would prevent the race. +DMA_ATTR_WEAK_ORDERING +---------------------- + +DMA_ATTR_WEAK_ORDERING specifies that reads and writes to the mapping +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. |