Re: [PATCH 2/3] media: v4l2-mc: Add debug prints for v4l2_fwnode_create_links_for_pad()

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

Thank you for the patch.

On Thu, Dec 21, 2023 at 03:58:21PM +0200, Sakari Ailus wrote:
> Add relevant debug prints for v4l2_fwnode_create_links_for_pad(). This
> should help debugging when things go wrong.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> # Renesas RZ/G2L SMARC
> ---
>  drivers/media/v4l2-core/v4l2-mc.c | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
> index 52d349e72b8c..b1a6246580ec 100644
> --- a/drivers/media/v4l2-core/v4l2-mc.c
> +++ b/drivers/media/v4l2-core/v4l2-mc.c
> @@ -337,12 +337,18 @@ int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
>  		src_idx = media_entity_get_fwnode_pad(&src_sd->entity,
>  						      endpoint,
>  						      MEDIA_PAD_FL_SOURCE);
> -		if (src_idx < 0)
> +		if (src_idx < 0) {
> +			dev_dbg(src_sd->dev, "no pad found for %pfw\n",
> +				endpoint);
>  			continue;
> +		}
>  
>  		remote_ep = fwnode_graph_get_remote_endpoint(endpoint);
> -		if (!remote_ep)
> +		if (!remote_ep) {
> +			dev_dbg(src_sd->dev, "no remote ep found for %pfw\n",
> +				endpoint);
>  			continue;
> +		}
>  
>  		/*
>  		 * ask the sink to verify it owns the remote endpoint,
> @@ -353,8 +359,12 @@ int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
>  						       MEDIA_PAD_FL_SINK);
>  		fwnode_handle_put(remote_ep);
>  
> -		if (sink_idx < 0 || sink_idx != sink->index)
> +		if (sink_idx < 0 || sink_idx != sink->index) {
> +			dev_dbg(src_sd->dev,
> +				"sink pad index mismatch or error (was %d, expected %u)\n",

s/was/is/

> +				sink_idx, sink->index);
>  			continue;
> +		}
>  
>  		/*
>  		 * the source endpoint corresponds to one of its source pads,
> @@ -367,8 +377,11 @@ int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
>  		src = &src_sd->entity.pads[src_idx];
>  
>  		/* skip if link already exists */
> -		if (media_entity_find_link(src, sink))
> +		if (media_entity_find_link(src, sink)) {
> +			dev_dbg(src_sd->dev, "link from %pfw to %pfw exists\n",
> +				endpoint, remote_ep);

Should this be printed using the entity names and pad numbers instead,
as done below ?

>  			continue;
> +		}
>  
>  		dev_dbg(src_sd->dev, "creating link %s:%d -> %s:%d\n",
>  			src_sd->entity.name, src_idx,

-- 
Regards,

Laurent Pinchart