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>
This commit is contained in:
Vinod Koul 2015-08-05 08:42:04 +05:30
parent 09659a5978
commit 06f10e2f93
1 changed files with 6 additions and 6 deletions

View File

@ -345,12 +345,12 @@ where to put them)
that abstracts it away.
* DMA_CTRL_ACK
- If set, the transfer can be reused after being completed.
- There is a guarantee the transfer won't be freed until it is acked
by async_tx_ack().
- As a consequence, if a device driver wants to skip the dma_map_sg() and
dma_unmap_sg() in between 2 transfers, because the DMA'd data wasn't used,
it can resubmit the transfer right after its completion.
- If clear, the descriptor cannot be reused by provider until the
client acknowledges receipt, i.e. has has a chance to establish any
dependency chains
- This can be acked by invoking async_tx_ack()
- If set, does not mean descriptor can be reused
General Design Notes
--------------------