diff options
author | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2022-01-13 17:00:42 +0200 |
---|---|---|
committer | Sakari Ailus <sakari.ailus@linux.intel.com> | 2022-03-04 00:27:06 +0200 |
commit | 3056a8e936bb090865402bfe6f3a730a28790033 (patch) | |
tree | dc9efe7ce7bb99f0264c24825220385ede80adf9 /drivers/media/mc | |
parent | f17bc788f7b97c36b8f3fbef14555a2a16ee3f69 (diff) |
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 'drivers/media/mc')
-rw-r--r-- | drivers/media/mc/mc-entity.c | 52 |
1 files changed, 22 insertions, 30 deletions
diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c index f83e043f0f3b..8ab0913d8d82 100644 --- a/drivers/media/mc/mc-entity.c +++ b/drivers/media/mc/mc-entity.c @@ -396,20 +396,21 @@ __must_check int __media_pipeline_start(struct media_entity *entity, struct media_link *link; int ret; - if (!pipe->streaming_count++) { - ret = media_graph_walk_init(&pipe->graph, mdev); - if (ret) - goto error_graph_walk_start; + if (pipe->streaming_count) { + pipe->streaming_count++; + return 0; } + ret = media_graph_walk_init(&pipe->graph, mdev); + if (ret) + return ret; + media_graph_walk_start(&pipe->graph, entity); while ((entity = media_graph_walk_next(graph))) { DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS); DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS); - entity->stream_count++; - if (entity->pipe && entity->pipe != pipe) { pr_err("Pipe active for %s. Can't start for %s\n", entity->name, @@ -418,12 +419,12 @@ __must_check int __media_pipeline_start(struct media_entity *entity, goto error; } - entity->pipe = pipe; - /* Already streaming --- no need to check. */ - if (entity->stream_count > 1) + if (entity->pipe) continue; + entity->pipe = pipe; + if (!entity->ops || !entity->ops->link_validate) continue; @@ -479,6 +480,8 @@ __must_check int __media_pipeline_start(struct media_entity *entity, } } + pipe->streaming_count++; + return 0; error: @@ -489,24 +492,17 @@ error: media_graph_walk_start(graph, entity_err); while ((entity_err = media_graph_walk_next(graph))) { - /* Sanity check for negative stream_count */ - if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) { - entity_err->stream_count--; - if (entity_err->stream_count == 0) - entity_err->pipe = NULL; - } + entity_err->pipe = NULL; /* - * We haven't increased stream_count further than this - * so we quit here. + * We haven't started entities further than this so we quit + * here. */ if (entity_err == entity) break; } -error_graph_walk_start: - if (!--pipe->streaming_count) - media_graph_walk_cleanup(graph); + media_graph_walk_cleanup(graph); return ret; } @@ -537,19 +533,15 @@ void __media_pipeline_stop(struct media_entity *entity) if (WARN_ON(!pipe)) return; + if (--pipe->streaming_count) + return; + media_graph_walk_start(graph, entity); - while ((entity = media_graph_walk_next(graph))) { - /* Sanity check for negative stream_count */ - if (!WARN_ON_ONCE(entity->stream_count <= 0)) { - entity->stream_count--; - if (entity->stream_count == 0) - entity->pipe = NULL; - } - } + while ((entity = media_graph_walk_next(graph))) + entity->pipe = NULL; - if (!--pipe->streaming_count) - media_graph_walk_cleanup(graph); + media_graph_walk_cleanup(graph); } EXPORT_SYMBOL_GPL(__media_pipeline_stop); |