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authorLinus Torvalds2022-10-22 15:30:15 -0700
committerLinus Torvalds2022-10-22 15:30:15 -0700
commit3272eb1ace32627d0ba1d20373fae246f46770ca (patch)
treef38aa2fcb12c92c3ef6b1f7e75960bb5d4b7b8e7 /Documentation/driver-api
parent4da34b7d175dc99b8befebd69e96546c960d526c (diff)
parentd67614f276c1499ad939fa5c1aadd35498cc6b34 (diff)
Merge tag 'media/v6.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull missed media updates from Mauro Carvalho Chehab: "It seems I screwed-up my previous pull request: it ends up that only half of the media patches that were in linux-next got merged in -rc1. The script which creates the signed tags silently failed due to 5.19->6.0 so it ended generating a tag with incomplete stuff. So here are the missing parts: - a DVB core security fix - lots of fixes and cleanups for atomisp staging driver - old drivers that are VB1 are being moved to staging to be deprecated - several driver updates - mostly for embedded systems, but there are also some things addressing issues with some PC webcams, in the UVC video driver" * tag 'media/v6.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (163 commits) media: sun6i-csi: Move csi buffer definition to main header file media: sun6i-csi: Introduce and use video helper functions media: sun6i-csi: Add media ops with link notify callback media: sun6i-csi: Remove controls handler from the driver media: sun6i-csi: Register the media device after creation media: sun6i-csi: Pass and store csi device directly in video code media: sun6i-csi: Tidy up video code media: sun6i-csi: Tidy up v4l2 code media: sun6i-csi: Tidy up Kconfig media: sun6i-csi: Use runtime pm for clocks and reset media: sun6i-csi: Define and use variant to get module clock rate media: sun6i-csi: Always set exclusive module clock rate media: sun6i-csi: Tidy up platform code media: sun6i-csi: Refactor main driver data structures media: sun6i-csi: Define and use driver name and (reworked) description media: cedrus: Add a Kconfig dependency on RESET_CONTROLLER media: sun8i-rotate: Add a Kconfig dependency on RESET_CONTROLLER media: sun8i-di: Add a Kconfig dependency on RESET_CONTROLLER media: sun4i-csi: Add a Kconfig dependency on RESET_CONTROLLER media: sun6i-csi: Add a Kconfig dependency on RESET_CONTROLLER ...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/media/mc-core.rst19
1 files changed, 15 insertions, 4 deletions
diff --git a/Documentation/driver-api/media/mc-core.rst b/Documentation/driver-api/media/mc-core.rst
index 84aa7cdb5341..400b8ca29367 100644
--- a/Documentation/driver-api/media/mc-core.rst
+++ b/Documentation/driver-api/media/mc-core.rst
@@ -214,18 +214,29 @@ 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.
+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_entity
+pipeline through the struct media_pad
pipe field.
Calls to :c:func:`media_pipeline_start()` can be nested.