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| author | Ingo Molnar <mingo@elte.hu> | 2009-01-18 14:15:05 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-01-18 14:15:05 -0500 |
| commit | 4092762aebfe55c1f8e31440b80a053c2dbe519b (patch) | |
| tree | 8fb9fd14131194174c12daf5d8195afd3b62bc3e /Documentation/DMA-API.txt | |
| parent | 745b1626dd71ce9661a05ea4db57859ed5c773d2 (diff) | |
| parent | 1de9e8e70f5acc441550ca75433563d91b269bbe (diff) | |
Merge branch 'tracing/ftrace'; commit 'v2.6.29-rc2' into tracing/core
Diffstat (limited to 'Documentation/DMA-API.txt')
| -rw-r--r-- | Documentation/DMA-API.txt | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index b462bb149543..52441694fe03 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt | |||
| @@ -170,16 +170,15 @@ Returns: 0 if successful and a negative error if not. | |||
| 170 | u64 | 170 | u64 |
| 171 | dma_get_required_mask(struct device *dev) | 171 | dma_get_required_mask(struct device *dev) |
| 172 | 172 | ||
| 173 | After setting the mask with dma_set_mask(), this API returns the | 173 | This API returns the mask that the platform requires to |
| 174 | actual mask (within that already set) that the platform actually | 174 | operate efficiently. Usually this means the returned mask |
| 175 | requires to operate efficiently. Usually this means the returned mask | ||
| 176 | is the minimum required to cover all of memory. Examining the | 175 | is the minimum required to cover all of memory. Examining the |
| 177 | required mask gives drivers with variable descriptor sizes the | 176 | required mask gives drivers with variable descriptor sizes the |
| 178 | opportunity to use smaller descriptors as necessary. | 177 | opportunity to use smaller descriptors as necessary. |
| 179 | 178 | ||
| 180 | Requesting the required mask does not alter the current mask. If you | 179 | Requesting the required mask does not alter the current mask. If you |
| 181 | wish to take advantage of it, you should issue another dma_set_mask() | 180 | wish to take advantage of it, you should issue a dma_set_mask() |
| 182 | call to lower the mask again. | 181 | call to set the mask to the value returned. |
| 183 | 182 | ||
| 184 | 183 | ||
| 185 | Part Id - Streaming DMA mappings | 184 | Part Id - Streaming DMA mappings |