Re: [PATCH v3 4/9] media: vimc: Separate starting stream from pipeline initialisation
From: Dafna Hirschfeld
Date: Fri Aug 21 2020 - 11:11:33 EST
Am 19.08.20 um 20:04 schrieb Kaaira Gupta:
Separate the process of initialising pipeline array from starting
streaming for all entities in path of a stream. This is needed because
multiple streams can stream, but only one pipeline object is needed.
Process frames only for those entities in a pipeline which are
streaming. This is known through their use counts.
Signed-off-by: Kaaira Gupta <kgupta@xxxxxxxxxxxxx>
---
.../media/test-drivers/vimc/vimc-streamer.c | 95 ++++++++++++++++---
1 file changed, 83 insertions(+), 12 deletions(-)
diff --git a/drivers/media/test-drivers/vimc/vimc-streamer.c b/drivers/media/test-drivers/vimc/vimc-streamer.c
index c1644d69686d..cc40ecabe95a 100644
--- a/drivers/media/test-drivers/vimc/vimc-streamer.c
+++ b/drivers/media/test-drivers/vimc/vimc-streamer.c
@@ -40,33 +40,30 @@ static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream)
}
/**
- * vimc_streamer_pipeline_init - Initializes the stream structure
+ * vimc_streamer_stream_start - Starts streaming for all entities
+ * in a stream
*
- * @stream: the pointer to the stream structure to be initialized
* @ved: the pointer to the vimc entity initializing the stream
*
- * Initializes the stream structure. Walks through the entity graph to
- * construct the pipeline used later on the streamer thread.
- * Calls vimc_streamer_s_stream() to enable stream in all entities of
- * the pipeline.
+ * Walks through the entity graph to call vimc_streamer_s_stream()
+ * to enable stream in all entities in path of a stream.
*
* Return: 0 if success, error code otherwise.
*/
-static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
- struct vimc_ent_device *ved)
+static int vimc_streamer_stream_start(struct vimc_stream *stream,
+ struct vimc_ent_device *ved)
{
struct media_entity *entity;
struct video_device *vdev;
struct v4l2_subdev *sd;
+ int stream_size = 0;
int ret = 0;
- stream->pipe_size = 0;
- while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
+ while (stream_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
if (!ved) {
vimc_streamer_pipeline_terminate(stream);
return -EINVAL;
}
- stream->ved_pipeline[stream->pipe_size++] = ved;
if (is_media_entity_v4l2_subdev(ved->ent)) {
sd = media_entity_to_v4l2_subdev(ved->ent);
@@ -104,6 +101,73 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
entity);
ved = video_get_drvdata(vdev);
}
+ stream_size++;
+ }
+
+ vimc_streamer_pipeline_terminate(stream);
+ return -EINVAL;
+}
+
+/**
+ * vimc_streamer_pipeline_init - Initialises pipeline and pipe size
+ *
+ * @stream: the pointer to the stream structure
+ * @ved: the pointer to the vimc entity initializing the stream pipeline
+ *
+ * Walks through the entity graph to initialise ved_pipeline and updates
+ * pipe_size too.
+ *
+ * Return: 0 if success, error code otherwise.
+ */
+static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
+ struct vimc_ent_device *ved)
+{
+ struct media_entity *entity;
+ struct media_device *mdev;
+ struct media_graph graph;
+ struct video_device *vdev;
+ struct v4l2_subdev *sd;
+ int ret;
+
+ entity = ved->ent;
+ mdev = entity->graph_obj.mdev;
+
+ ret = media_graph_walk_init(&graph, mdev);
+ if (ret)
+ return ret;
+
+ media_graph_walk_start(&graph, entity);
+
+ /*
+ * Start pipeline array initialisation from RAW Capture only to get
+ * entities in the correct order of their frame processing.
+ */
+ if (!strncmp(entity->name, "RGB", 3)) {
I don't understand this condition, way is it good for?
I think the function should be generic and not assume names of entities
or specific topology.
+ entity = media_graph_walk_next(&graph);
+ mdev = entity->graph_obj.mdev;
+ media_graph_walk_cleanup(&graph);
+
+ ret = media_graph_walk_init(&graph, mdev);
+ if (ret)
+ return ret;
+ media_graph_walk_start(&graph, entity);
+ }
+
+ while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
+ if (is_media_entity_v4l2_subdev(entity)) {
+ sd = media_entity_to_v4l2_subdev(entity);
+ ved = v4l2_get_subdevdata(sd);
+ } else {
+ vdev = container_of(entity, struct video_device, entity);
+ ved = video_get_drvdata(vdev);
+ }
+ stream->ved_pipeline[stream->pipe_size++] = ved;
+ entity = media_graph_walk_next(&graph);
+
+ if (!strcmp(entity->name, stream->ved_pipeline[0]->ent->name)) {
I also don't understand this condition
+ media_graph_walk_cleanup(&graph);
+ return 0;
+ }
}
It is not clear what this function does, it looks like it adds to 'ved_pipeline'
all entities that are connected to the video node, in addition to the entities
that where there from previous calls, so some entities appear several times.
I think there is no need to use the graph walk here but to access the source entity
in each iteration, the way done in vimc_streamer_stream_start
also.
I think the code should iterate here until it reaches an entity that is already streaming,
this means that the entity is already in the `ved_pipeline`, also you should make sure
that the sensor is the first entity that process a frame, therefore the sensor should be
at the end/start of the list of entities. Generally each entity should appear exactly once
in the 'ved_pipeline' array and the entities should be ordered such that when calling 'process_frame'
on one entity should be after calling 'process_frame' on its source entity.
maybe it is easyer to implement if 'ved_pipeline' is a linked list.
Thanks,
Dafna
vimc_streamer_pipeline_terminate(stream);
@@ -138,8 +202,11 @@ static int vimc_streamer_thread(void *data)
for (i = stream->pipe_size - 1; i >= 0; i--) {
ved = stream->ved_pipeline[i];
- ret = ved->process_frame(ved);
+ if (atomic_read(&ved->use_count) == 0)
+ continue;
+
+ ret = ved->process_frame(ved);
if (ret)
break;
}
@@ -179,6 +246,10 @@ int vimc_streamer_s_stream(struct vimc_stream *stream,
if (stream->kthread)
return 0;
+ ret = vimc_streamer_stream_start(stream, ved);
+ if (ret)
+ return ret;
+
ret = vimc_streamer_pipeline_init(stream, ved);
if (ret)
return ret;