Re: [PATCH v2.2 2/4] media: Check for active links on pads with MEDIA_PAD_FL_MUST_CONNECT flag

Laurent Pinchart
2013-10-31T14:46:12Z

Hi Sakari,

Thank you for the patch.

On Wednesday 16 October 2013 00:48:17 Sakari Ailus wrote:
> Do not allow streaming if a pad with MEDIA_PAD_FL_MUST_CONNECT flag is not
> connected by an active link.
>
> This patch makes it possible to avoid drivers having to check for the most
> common case of link state validation: a sink pad that must be connected.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

I've taken the whole series in my tree and will push it upstream for v3.14.

> ---
> drivers/media/media-entity.c | 41 ++++++++++++++++++++++++++++++++-------
> 1 file changed, 34 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
> index 2c286c3..37c334e 100644
> --- a/drivers/media/media-entity.c
> +++ b/drivers/media/media-entity.c
> @@ -235,6 +235,8 @@ __must_check int media_entity_pipeline_start(struct
> media_entity *entity, media_entity_graph_walk_start(&graph, entity);
>
> while ((entity = media_entity_graph_walk_next(&graph))) {
> + DECLARE_BITMAP(active, entity->num_pads);
> + DECLARE_BITMAP(has_no_links, entity->num_pads);
> unsigned int i;
>
> entity->stream_count++;
> @@ -248,21 +250,46 @@ __must_check int media_entity_pipeline_start(struct
> media_entity *entity, if (!entity->ops || !entity->ops->link_validate)
> continue;
>
> + bitmap_zero(active, entity->num_pads);
> + bitmap_fill(has_no_links, entity->num_pads);
> +
> for (i = 0; i < entity->num_links; i++) {
> struct media_link *link = &entity->links[i];
> -
> - /* Is this pad part of an enabled link? */
> - if (!(link->flags & MEDIA_LNK_FL_ENABLED))
> - continue;
> -
> - /* Are we the sink or not? */
> - if (link->sink->entity != entity)
> + struct media_pad *pad = link->sink->entity == entity
> + ? link->sink : link->source;
> +
> + /* Mark that a pad is connected by a link. */
> + bitmap_clear(has_no_links, pad->index, 1);
> +
> + /*
> + * Pads that either do not need to connect or
> + * are connected through an enabled link are
> + * fine.
> + */
> + if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
> + link->flags & MEDIA_LNK_FL_ENABLED)
> + bitmap_set(active, pad->index, 1);
> +
> + /*
> + * Link validation will only take place for
> + * sink ends of the link that are enabled.
> + */
> + if (link->sink != pad ||
> + !(link->flags & MEDIA_LNK_FL_ENABLED))
> continue;
>
> ret = entity->ops->link_validate(link);
> if (ret < 0 && ret != -ENOIOCTLCMD)
> goto error;
> }
> +
> + /* Either no links or validated links are fine. */
> + bitmap_or(active, active, has_no_links, entity->num_pads);
> +
> + if (!bitmap_full(active, entity->num_pads)) {
> + ret = -EPIPE;
> + goto error;
> + }
> }
>
> mutex_unlock(&mdev->graph_mutex);
--
Regards,

Laurent Pinchart