diff options
| -rw-r--r-- | drivers/media/v4l2-core/v4l2-subdev.c | 43 | ||||
| -rw-r--r-- | include/media/v4l2-subdev.h | 6 |
2 files changed, 44 insertions, 5 deletions
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index d3196042d5c5..3a4ba08810d2 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -1450,13 +1450,46 @@ int v4l2_subdev_link_validate(struct media_link *link) if (WARN_ON_ONCE(!is_media_entity_v4l2_subdev(link->sink->entity))) return -EINVAL; - if (!is_media_entity_v4l2_subdev(link->source->entity)) { - pr_warn_once("source of link '%s':%u->'%s':%u is not a V4L2 sub-device, driver bug!\n", - link->source->entity->name, link->source->index, - link->sink->entity->name, link->sink->index); - return 0; + /* + * If the source is a video device, delegate link validation to it. This + * allows usage of this helper for subdev connected to a video output + * device, provided that the driver implement the video output device's + * .link_validate() operation. + */ + if (is_media_entity_v4l2_video_device(link->source->entity)) { + struct media_entity *source = link->source->entity; + + if (!source->ops || !source->ops->link_validate) { + /* + * Many existing drivers do not implement the required + * .link_validate() operation for their video devices. + * Print a warning to get the drivers fixed, and return + * 0 to avoid breaking userspace. This should + * eventually be turned into a WARN_ON() when all + * drivers will have been fixed. + */ + pr_warn_once("video device '%s' does not implement .link_validate(), driver bug!\n", + source->name); + return 0; + } + + /* + * Avoid infinite loops in case a video device incorrectly uses + * this helper function as its .link_validate() handler. + */ + if (WARN_ON(source->ops->link_validate == v4l2_subdev_link_validate)) + return -EINVAL; + + return source->ops->link_validate(link); } + /* + * If the source is still not a subdev, usage of this helper is a clear + * driver bug. + */ + if (WARN_ON(!is_media_entity_v4l2_subdev(link->source->entity))) + return -EINVAL; + sink_sd = media_entity_to_v4l2_subdev(link->sink->entity); source_sd = media_entity_to_v4l2_subdev(link->source->entity); diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index bd235d325ff9..8daa0929865c 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -1250,6 +1250,12 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd, * calls v4l2_subdev_link_validate_default() to ensure that * width, height and the media bus pixel code are equal on both * source and sink of the link. + * + * The function can be used as a drop-in &media_entity_ops.link_validate + * implementation for v4l2_subdev instances. It supports all links between + * subdevs, as well as links between subdevs and video devices, provided that + * the video devices also implement their &media_entity_ops.link_validate + * operation. */ int v4l2_subdev_link_validate(struct media_link *link); |