diff options
| author | Vinod Koul <vinod.koul@intel.com> | 2015-08-04 23:12:04 -0400 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2015-08-17 04:16:22 -0400 |
| commit | 06f10e2f936424496d44e5541c220845c8c55345 (patch) | |
| tree | 5ae6aea36ea8370ec4ae1e0abadcafadb87eddf0 /Documentation/dmaengine | |
| parent | 09659a5978e16a7f3676fd6cb41e21daa77ce9a6 (diff) | |
Documentation: dmaengine: fix the DMA_CTRL_ACK documentation
As discussed recently the meaning of DMA_CTRL_ACK is that a desc cannot be
reused by provider until the client acknowledges receipt, i.e. has has a
chance to establish any dependency chains. So update documentation
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Acked-by:Robert Jarzmik <robert.jarzmik@free.fr>
Diffstat (limited to 'Documentation/dmaengine')
| -rw-r--r-- | Documentation/dmaengine/provider.txt | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt index ca67b0f04c6e..243889ec5c5a 100644 --- a/Documentation/dmaengine/provider.txt +++ b/Documentation/dmaengine/provider.txt | |||
| @@ -345,12 +345,12 @@ where to put them) | |||
| 345 | that abstracts it away. | 345 | that abstracts it away. |
| 346 | 346 | ||
| 347 | * DMA_CTRL_ACK | 347 | * DMA_CTRL_ACK |
| 348 | - If set, the transfer can be reused after being completed. | 348 | - If clear, the descriptor cannot be reused by provider until the |
| 349 | - There is a guarantee the transfer won't be freed until it is acked | 349 | client acknowledges receipt, i.e. has has a chance to establish any |
| 350 | by async_tx_ack(). | 350 | dependency chains |
| 351 | - As a consequence, if a device driver wants to skip the dma_map_sg() and | 351 | - This can be acked by invoking async_tx_ack() |
| 352 | dma_unmap_sg() in between 2 transfers, because the DMA'd data wasn't used, | 352 | - If set, does not mean descriptor can be reused |
| 353 | it can resubmit the transfer right after its completion. | 353 | |
| 354 | 354 | ||
| 355 | General Design Notes | 355 | General Design Notes |
| 356 | -------------------- | 356 | -------------------- |
