diff options
| author | Paul Kocialkowski <paul.kocialkowski@bootlin.com> | 2022-03-31 16:41:14 +0300 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2022-04-11 16:45:52 +0300 |
| commit | 1f854536a8336c61c89ab040bbc874c75325d37c (patch) | |
| tree | a9739dd8adb01bee9409eeda0e887c0128cddb3d /Documentation/driver-api/dmaengine/provider.rst | |
| parent | ec834f1cc7cf471b090bb0a6ee077a7bb90a3549 (diff) | |
| download | linux-1f854536a8336c61c89ab040bbc874c75325d37c.tar.xz | |
dmaengine: Clarify cyclic transfer residue documentation
The current documentation for the residue reported in a cyclic transfer
case mentions that the reported residue should be relative to the current
period only. However the definition of DMA_RESIDUE_GRANULARITY_SEGMENT
specifies that the residue should be updated after each period for
a cyclic transfer, which is in direct contradiction.
Moreover the pcm_dmaengine common code uses the residue relative to
the whole cyclic buffer size, not one period.
Correct the residue-related documentation to reflect this.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Link: https://lore.kernel.org/r/20220331134114.703782-1-paul.kocialkowski@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'Documentation/driver-api/dmaengine/provider.rst')
| -rw-r--r-- | Documentation/driver-api/dmaengine/provider.rst | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/driver-api/dmaengine/provider.rst b/Documentation/driver-api/dmaengine/provider.rst index 0072c9c7efd3..d3fa80e333b1 100644 --- a/Documentation/driver-api/dmaengine/provider.rst +++ b/Documentation/driver-api/dmaengine/provider.rst @@ -457,7 +457,7 @@ supported. - Should use dma_set_residue to report it - In the case of a cyclic transfer, it should only take into - account the current period. + account the total size of the cyclic buffer. - Should return DMA_OUT_OF_ORDER if the device does not support in order completion and is completing the operation out of order. |