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Diffstat (limited to 'Documentation/driver-api/media/mc-core.rst')
| -rw-r--r-- | Documentation/driver-api/media/mc-core.rst | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/Documentation/driver-api/media/mc-core.rst b/Documentation/driver-api/media/mc-core.rst index 02481a2513b9..2456950ce8ff 100644 --- a/Documentation/driver-api/media/mc-core.rst +++ b/Documentation/driver-api/media/mc-core.rst @@ -186,8 +186,9 @@ is required and the graph structure can be freed normally. Helper functions can be used to find a link between two given pads, or a pad connected to another pad through an enabled link -:c:func:`media_entity_find_link()` and -:c:func:`media_entity_remote_pad()`. +(:c:func:`media_entity_find_link()`, :c:func:`media_pad_remote_pad_first()`, +:c:func:`media_entity_remote_source_pad_unique()` and +:c:func:`media_pad_remote_pad_unique()`). Use count and power handling ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -213,19 +214,28 @@ Link properties can be modified at runtime by calling Pipelines and media streams ^^^^^^^^^^^^^^^^^^^^^^^^^^^ +A media stream is a stream of pixels or metadata originating from one or more +source devices (such as a sensors) and flowing through media entity pads +towards the final sinks. The stream can be modified on the route by the +devices (e.g. scaling or pixel format conversions), or it can be split into +multiple branches, or multiple branches can be merged. + +A media pipeline is a set of media streams which are interdependent. This +interdependency can be caused by the hardware (e.g. configuration of a second +stream cannot be changed if the first stream has been enabled) or by the driver +due to the software design. Most commonly a media pipeline consists of a single +stream which does not branch. + When starting streaming, drivers must notify all entities in the pipeline to prevent link states from being modified during streaming by calling :c:func:`media_pipeline_start()`. -The function will mark all entities connected to the given entity through -enabled links, either directly or indirectly, as streaming. +The function will mark all the pads which are part of the pipeline as streaming. -The struct media_pipeline instance pointed to by -the pipe argument will be stored in every entity in the pipeline. -Drivers should embed the struct media_pipeline -in higher-level pipeline structures and can then access the -pipeline through the struct media_entity -pipe field. +The struct media_pipeline instance pointed to by the pipe argument will be +stored in every pad in the pipeline. Drivers should embed the struct +media_pipeline in higher-level pipeline structures and can then access the +pipeline through the struct media_pad pipe field. Calls to :c:func:`media_pipeline_start()` can be nested. The pipeline pointer must be identical for all nested calls to the function. |