Re: [PATCH v2 04/30] v4l: mc: Start walk from a specific pad in use count calculation

[Sakari Ailus <sakari.ailus@linux.intel.com>]

On Wed, Jan 16, 2019 at 12:24:32AM +0200, Laurent Pinchart wrote:
> Hi Niklas,
> 
> Thank you for the patch.
> 
> On Fri, Nov 02, 2018 at 12:31:18AM +0100, Niklas Söderlund wrote:
> > From: Sakari Ailus <sakari.ailus@linux.intel.com>
> > 
> > With the addition of the recent has_route() media entity op, the pads of a
> > media entity are no longer all interconnected. This has to be taken into
> > account in power management.
> > 
> > Prepare for the addition of a helper function supporting S_ROUTING.
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > ---
> >  drivers/media/v4l2-core/v4l2-mc.c | 25 ++++++++++++-------------
> >  1 file changed, 12 insertions(+), 13 deletions(-)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
> > index 98edd47b2f0ae747..208cd91ce57ff211 100644
> > --- a/drivers/media/v4l2-core/v4l2-mc.c
> > +++ b/drivers/media/v4l2-core/v4l2-mc.c
> > @@ -332,17 +332,16 @@ EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
> >  
> >  /*
> >   * pipeline_pm_use_count - Count the number of users of a pipeline
> > - * @entity: The entity
> > + * @pad: The pad
> 
> That's not very descriptive (I know it wasn't to start with either). How
> about "Any pad part of the pipeline" ?

How about: "Any pad along the pipeline"?

> 
> >   *
> >   * Return the total number of users of all video device nodes in the pipeline.
> >   */
> > -static int pipeline_pm_use_count(struct media_entity *entity,
> > -	struct media_graph *graph)
> > +static int pipeline_pm_use_count(struct media_pad *pad,
> > +				 struct media_graph *graph)
> >  {
> > -	struct media_pad *pad;
> >  	int use = 0;
> >  
> > -	media_graph_walk_start(graph, entity->pads);
> > +	media_graph_walk_start(graph, pad);
> >  
> >  	while ((pad = media_graph_walk_next(graph))) {
> >  		if (is_media_entity_v4l2_video_device(pad->entity))
> > @@ -388,7 +387,7 @@ static int pipeline_pm_power_one(struct media_entity *entity, int change)
> >  
> >  /*
> >   * pipeline_pm_power - Apply power change to all entities in a pipeline
> > - * @entity: The entity
> > + * @pad: The pad
> 
> Same here.
> 
> With this fixed,
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> >   * @change: Use count change
> >   *
> >   * Walk the pipeline to update the use count and the power state of all non-node
> > @@ -396,16 +395,16 @@ static int pipeline_pm_power_one(struct media_entity *entity, int change)
> >   *
> >   * Return 0 on success or a negative error code on failure.
> >   */
> > -static int pipeline_pm_power(struct media_entity *entity, int change,
> > +static int pipeline_pm_power(struct media_pad *pad, int change,
> >  	struct media_graph *graph)
> >  {
> > -	struct media_pad *tmp_pad, *pad;
> > +	struct media_pad *tmp_pad, *first = pad;
> >  	int ret = 0;
> >  
> >  	if (!change)
> >  		return 0;
> >  
> > -	media_graph_walk_start(graph, entity->pads);
> > +	media_graph_walk_start(graph, pad);
> >  
> >  	while (!ret && (pad = media_graph_walk_next(graph)))
> >  		if (is_media_entity_v4l2_subdev(pad->entity))
> > @@ -414,7 +413,7 @@ static int pipeline_pm_power(struct media_entity *entity, int change,
> >  	if (!ret)
> >  		return ret;
> >  
> > -	media_graph_walk_start(graph, entity->pads);
> > +	media_graph_walk_start(graph, first);
> >  
> >  	while ((tmp_pad = media_graph_walk_next(graph))
> >  	       && tmp_pad != pad)
> > @@ -437,7 +436,7 @@ int v4l2_pipeline_pm_use(struct media_entity *entity, int use)
> >  	WARN_ON(entity->use_count < 0);
> >  
> >  	/* Apply power change to connected non-nodes. */
> > -	ret = pipeline_pm_power(entity, change, &mdev->pm_count_walk);
> > +	ret = pipeline_pm_power(entity->pads, change, &mdev->pm_count_walk);
> >  	if (ret < 0)
> >  		entity->use_count -= change;
> >  
> > @@ -451,8 +450,8 @@ int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
> >  			      unsigned int notification)
> >  {
> >  	struct media_graph *graph = &link->graph_obj.mdev->pm_count_walk;
> > -	struct media_entity *source = link->source->entity;
> > -	struct media_entity *sink = link->sink->entity;
> > +	struct media_pad *source = link->source;
> > +	struct media_pad *sink = link->sink;
> >  	int source_use;
> >  	int sink_use;
> >  	int ret = 0;
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Sakari Ailus
sakari.ailus@linux.intel.com