3056a8e936
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> |
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| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kunit | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| vdso | ||
| video | ||
| xen | ||