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| author | Sakari Ailus <sakari.ailus@iki.fi> | 2011-10-11 00:01:25 +0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-05-14 15:45:31 +0400 |
| commit | 8227c92b69688403dee2adf5f399a49539ae5049 (patch) | |
| tree | b9f4775e4f9ed99c41aca6cf6334aaef6f861d69 /Documentation/video4linux/v4l2-framework.txt | |
| parent | 48398f932b4ddcc8fa9a890595645cc14f6889a8 (diff) | |
| download | linux-8227c92b69688403dee2adf5f399a49539ae5049.tar.xz | |
[media] v4l: Implement v4l2_subdev_link_validate()
v4l2_subdev_link_validate() is the default op for validating a link. In V4L2
subdev context, it is used to call a pad op which performs the proper link
check without much extra work.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/video4linux/v4l2-framework.txt')
| -rw-r--r-- | Documentation/video4linux/v4l2-framework.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 493ffd1b1cf5..fe53177f0d3c 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -316,6 +316,18 @@ If the subdev driver intends to process video and integrate with the media framework, it must implement format related functionality using v4l2_subdev_pad_ops instead of v4l2_subdev_video_ops. +In that case, the subdev driver may set the link_validate field to provide +its own link validation function. The link validation function is called for +every link in the pipeline where both of the ends of the links are V4L2 +sub-devices. The driver is still responsible for validating the correctness +of the format configuration between sub-devices and video nodes. + +If link_validate op is not set, the default function +v4l2_subdev_link_validate_default() is used instead. This function ensures +that width, height and the media bus pixel code are equal on both source and +sink of the link. Subdev drivers are also free to use this function to +perform the checks mentioned above in addition to their own checks. + A device (bridge) driver needs to register the v4l2_subdev with the v4l2_device: |