4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit c5ff0edb8e2270a75935c73217fb0de1abd2d910 ]
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 any entity in the graph is actively involved in streaming (because modifying the CHSEL register fields can disrupt any/all running streams), then the entities stream counts should be checked rather than the use counts.
(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, but that is insufficient, since there should be no running streams in the entire graph).
Modify the code block to check the entity stream_count instead of the use_count (and elaborate on the comment). VIN node links can now be enabled even if there are other independent in-use entities that are not streaming.
Fixes: c0cc5aef31 ("media: rcar-vin: add link notify for Gen3")
Signed-off-by: Steve Longerbeam slongerbeam@gmail.com Reviewed-by: Niklas Söderlund niklas.soderlund+renesas@ragnatech.se Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab+samsung@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/platform/rcar-vin/rcar-core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c index ce09799976ef..e1085e3ab3cc 100644 --- a/drivers/media/platform/rcar-vin/rcar-core.c +++ b/drivers/media/platform/rcar-vin/rcar-core.c @@ -131,9 +131,13 @@ 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. */ + /* + * Don't allow link changes if any entity in the graph is + * streaming, modifying the CHSEL register fields can disrupt + * running streams. + */ media_device_for_each_entity(entity, &group->mdev) - if (entity->use_count) + if (entity->stream_count) return -EBUSY;
mutex_lock(&group->lock);