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| author | Vinod Koul <vinod.koul@intel.com> | 2015-06-25 06:51:37 +0300 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2015-06-25 06:51:37 +0300 |
| commit | 9324fdf5267b12f6db660fe52e882bbfffcc109a (patch) | |
| tree | 877a81ac336724efdb02403eceb8ca0b1e7b10eb /Documentation | |
| parent | 4983a501afede12f95d26e1e213f8f2e9eda1871 (diff) | |
| parent | 5f88d9706fa48084eaab2dbbec27779809c5106b (diff) | |
| download | linux-9324fdf5267b12f6db660fe52e882bbfffcc109a.tar.xz | |
Merge branch 'topic/core' into for-linus
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/dmaengine/provider.txt | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt index 05d2280190f1..ca67b0f04c6e 100644 --- a/Documentation/dmaengine/provider.txt +++ b/Documentation/dmaengine/provider.txt @@ -345,11 +345,12 @@ where to put them) that abstracts it away. * DMA_CTRL_ACK - - Undocumented feature - - No one really has an idea of what it's about, besides being - related to reusing the DMA transaction descriptors or having - additional transactions added to it in the async-tx API - - Useless in the case of the slave API + - 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. General Design Notes -------------------- |