Hi Laurent
On 30/07/2024 16:09, Laurent Pinchart wrote:
Hi Dan,
Thank you for the patch.
On Tue, Jul 09, 2024 at 02:28:49PM +0100, Daniel Scally wrote:
Record the number of video devices in a pipeline so that we can track
in a central location how many need to be started before drivers must
actually begin streaming.
Signed-off-by: Daniel Scally <dan.scally@xxxxxxxxxxxxxxxx>
---
Changes in v6:
- New patch. This is intended to support Sakari's requirement for the
driver not to start streaming before all of the video devices have
called streamon(). This was the cleanest way I could think to acheive
the goal, and lets us just check for start_count == required_count
before streaming.
This violates the abstraction layers a bit, the MC code isn't supposed
to handle video devices like that.
What you can instead do is to use media_pipeline_for_each_entity() in
your driver when starting the pipeline to iterate over all entities, and
count the video devices there.
That'll do! Thanks for the suggestion.
drivers/media/mc/mc-entity.c | 5 +++++
include/media/media-entity.h | 2 ++
2 files changed, 7 insertions(+)
diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c
index 96dd0f6ccd0d..1e8186b13b55 100644
--- a/drivers/media/mc/mc-entity.c
+++ b/drivers/media/mc/mc-entity.c
@@ -596,6 +596,9 @@ static int media_pipeline_add_pad(struct media_pipeline *pipe,
list_add_tail(&ppad->list, &pipe->pads);
+ if (pad->entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE)
+ pipe->required_count++;
+
dev_dbg(pad->graph_obj.mdev->dev,
"media pipeline: added pad '%s':%u\n",
pad->entity->name, pad->index);
@@ -713,6 +716,8 @@ static void media_pipeline_cleanup(struct media_pipeline *pipe)
list_del(&ppad->list);
kfree(ppad);
}
+
+ pipe->required_count = 0;
}
static int media_pipeline_populate(struct media_pipeline *pipe,
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 0393b23129eb..ab84458b40dc 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -104,12 +104,14 @@ struct media_graph {
* @mdev: The media device the pipeline is part of
* @pads: List of media_pipeline_pad
* @start_count: Media pipeline start - stop count
+ * @required_count: Number of starts required to be "running"
*/
struct media_pipeline {
bool allocated;
struct media_device *mdev;
struct list_head pads;
int start_count;
+ int required_count;
};
/**
