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| author | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2022-01-13 18:00:42 +0300 |
|---|---|---|
| committer | Sakari Ailus <sakari.ailus@linux.intel.com> | 2022-03-04 01:27:06 +0300 |
| commit | 3056a8e936bb090865402bfe6f3a730a28790033 (patch) | |
| tree | dc9efe7ce7bb99f0264c24825220385ede80adf9 /include/media | |
| parent | f17bc788f7b97c36b8f3fbef14555a2a16ee3f69 (diff) | |
| download | linux-3056a8e936bb090865402bfe6f3a730a28790033.tar.xz | |
media: media-entity: Simplify media_pipeline_start()
The media_pipeline_start() function has two purposes: it constructs a
pipeline by recording the entities that are part of it, gathered from a
graph walk, and validate the media links. The pipeline pointer is stored
in the media_entity structure as part of this process, and the entity's
stream count is increased, to record that the entity is streaming.
When multiple video nodes are present in a pipeline,
media_pipeline_start() is typically called on all of them, with the same
pipeline pointer. This is taken into account in media_pipeline_start()
by skipping validation for entities that are already part of the
pipeline, while returning an error if an entity is part of a different
pipeline.
It turns out that this process is overly complicated. When
media_pipeline_start() is called for the first time, it constructs the
full pipeline, adding all entities and validating all the links.
Subsequent calls to media_pipeline_start() are then nearly no-ops, they
only increase the stream count on the pipeline and on all entities.
The media_entity stream_count field is used for two purposes: checking
if the entity is streaming, and detecting when a call to
media_pipeline_stop() balances needs to reset the entity pipe pointer to
NULL. The former can easily be replaced by a check of the pipe pointer.
Simplify media_pipeline_start() by avoiding the pipeline walk on all
calls but the first one, and drop the media_entity stream_count field.
media_pipeline_stop() is updated accordingly.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Sakari Ailus: Drop redundant '!= NULL' as discussed]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Diffstat (limited to 'include/media')
| -rw-r--r-- | include/media/media-entity.h | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 8546f13c42a9..33ee595c13f4 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -268,7 +268,6 @@ enum media_entity_type { * @pads: Pads array with the size defined by @num_pads. * @links: List of data links. * @ops: Entity operations. - * @stream_count: Stream count for the entity. * @use_count: Use count for the entity. * @pipe: Pipeline this entity belongs to. * @info: Union with devnode information. Kept just for backward @@ -283,10 +282,9 @@ enum media_entity_type { * * .. note:: * - * @stream_count and @use_count reference counts must never be - * negative, but are signed integers on purpose: a simple ``WARN_ON(<0)`` - * check can be used to detect reference count bugs that would make them - * negative. + * The @use_count reference count must never be negative, but is a signed + * integer on purpose: a simple ``WARN_ON(<0)`` check can be used to detect + * reference count bugs that would make it negative. */ struct media_entity { struct media_gobj graph_obj; /* must be first field in struct */ @@ -305,7 +303,6 @@ struct media_entity { const struct media_entity_operations *ops; - int stream_count; int use_count; struct media_pipeline *pipe; @@ -867,7 +864,7 @@ struct media_pad *media_entity_remote_pad(const struct media_pad *pad); */ static inline bool media_entity_is_streaming(const struct media_entity *entity) { - return entity->stream_count > 0; + return entity->pipe; } /** |