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| author |   Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2022-07-08 17:21:40 +0100 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab@kernel.org> | 2022-07-15 16:17:31 +0100 |
| commit | 64fe675e999c2c7d753ecaaa1349693c59ce6c11 (patch) | |
| tree | dd3e899b19fef36aae1029dcf6a150bee5c1c068 /Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst | |
| parent | media: venus: set ubwc configuration on specific video hardware (diff) | |
| download | wireguard-linux-64fe675e999c2c7d753ecaaa1349693c59ce6c11.tar.xz wireguard-linux-64fe675e999c2c7d753ecaaa1349693c59ce6c11.zip | |
media: videodev2.h: add V4L2_CTRL_FLAG_DYNAMIC_ARRAY
Add a new flag that indicates that this control is a dynamically sized
array. Also document this flag.
Currently dynamically sized arrays are limited to one dimensional arrays,
but that might change in the future if there is a need for it.
The initial use-case of dynamic arrays are stateless codecs. A frame
can be divided in many slices, so you want to provide an array containing
slice information for each slice. Typically the number of slices is small,
but the standard allow for hundreds or thousands of slices. Dynamic arrays
are a good solution since sizing the array for the worst case would waste
substantial amounts of memory.
Acked-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Tested-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst index 88f630252d98..a20dfa2a933b 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst @@ -625,6 +625,14 @@ See also the examples in :ref:`control`. ``V4L2_CTRL_FLAG_GRABBED`` flag when buffers are allocated or streaming is in progress since most drivers do not support changing the format in that case. + * - ``V4L2_CTRL_FLAG_DYNAMIC_ARRAY`` + - 0x0800 + - This control is a dynamically sized 1-dimensional array. It + behaves the same as a regular array, except that the number + of elements as reported by the ``elems`` field is between 1 and + ``dims[0]``. So setting the control with a differently sized + array will change the ``elems`` field when the control is + queried afterwards. Return Value ============ |