[RFC PATCH] media: rcar-vin: Allow independent VIN link enablement

Steve Longerbeam
2018-12-25T23:27:36Z

There is a block of code in rvin_group_link_notify() that prevents
enabling a link to a VIN node if any entity in the media graph is
in use. This prevents enabling a VIN link even if there is an in-use
entity somewhere in the graph that is independent of the link's
pipeline.

For example, the code block will prevent enabling a link from
the first rcar-csi2 receiver to a VIN node even if there is an
enabled link somewhere far upstream on the second independent
rcar-csi2 receiver pipeline.

If this code block is meant to prevent modifying a link if the
link is actively involved in streaming, there is already such a
check in __media_entity_setup_link() that verifies the stream_count
of the link's source and sink entities are both zero.

Remove the code block so that VIN node links can be enabled even if
there are other independent in-use entities.

Fixes: c0cc5aef31 ("media: rcar-vin: add link notify for Gen3")

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
---
drivers/media/platform/rcar-vin/rcar-core.c | 6 ------
1 file changed, 6 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index f0719ce24b97..b2c9a876969e 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -116,7 +116,6 @@ static int rvin_group_link_notify(struct media_link *link, u32 flags,
struct rvin_group, mdev);
unsigned int master_id, channel, mask_new, i;
unsigned int mask = ~0;
- struct media_entity *entity;
struct video_device *vdev;
struct media_pad *csi_pad;
struct rvin_dev *vin = NULL;
@@ -131,11 +130,6 @@ static int rvin_group_link_notify(struct media_link *link, u32 flags,
!is_media_entity_v4l2_video_device(link->sink->entity))
return 0;

- /* If any entity is in use don't allow link changes. */
- media_device_for_each_entity(entity, &group->mdev)
- if (entity->use_count)
- return -EBUSY;
-
mutex_lock(&group->lock);

/* Find the master VIN that controls the routes. */
--
2.17.1