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Diffstat (limited to 'Documentation/video4linux')
| -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 493ffd1b1cf..fe53177f0d3 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: |