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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2022-01-13 18:00:42 +0300
committerSakari Ailus <sakari.ailus@linux.intel.com>2022-03-04 01:27:06 +0300
commit3056a8e936bb090865402bfe6f3a730a28790033 (patch)
treedc9efe7ce7bb99f0264c24825220385ede80adf9 /include/media
parentf17bc788f7b97c36b8f3fbef14555a2a16ee3f69 (diff)
downloadlinux-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.h11
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;
}
/**