Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-22 12:11:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

media: videodev2.h: add V4L2_CTRL_FLAG_DYNAMIC_ARRAY

Browse Source 
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>
This commit is contained in:
Hans Verkuil 2022-07-08 17:21:40 +01:00 committed by Mauro Carvalho Chehab
parent b228cf38f0
commit 64fe675e99
3 changed files with 10 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
View File

@ -625,6 +625,14 @@ See also the examples in :ref:`control`.
``V4L2_CTRL_FLAG_GRABBED`` flag when buffers are allocated or ``V4L2_CTRL_FLAG_GRABBED`` flag when buffers are allocated or
streaming is in progress since most drivers do not support changing streaming is in progress since most drivers do not support changing
the format in that case. 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 Return Value
============ ============

1
Documentation/userspace-api/media/videodev2.h.rst.exceptions
View File

@ -379,6 +379,7 @@ replace define V4L2_CTRL_FLAG_VOLATILE control-flags
replace define V4L2_CTRL_FLAG_HAS_PAYLOAD control-flags replace define V4L2_CTRL_FLAG_HAS_PAYLOAD control-flags
replace define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE control-flags replace define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE control-flags
replace define V4L2_CTRL_FLAG_MODIFY_LAYOUT control-flags replace define V4L2_CTRL_FLAG_MODIFY_LAYOUT control-flags
replace define V4L2_CTRL_FLAG_DYNAMIC_ARRAY control-flags
replace define V4L2_CTRL_FLAG_NEXT_CTRL control replace define V4L2_CTRL_FLAG_NEXT_CTRL control
replace define V4L2_CTRL_FLAG_NEXT_COMPOUND control replace define V4L2_CTRL_FLAG_NEXT_COMPOUND control

1
include/uapi/linux/videodev2.h
View File

@ -1914,6 +1914,7 @@ struct v4l2_querymenu {
#define V4L2_CTRL_FLAG_HAS_PAYLOAD 0x0100 #define V4L2_CTRL_FLAG_HAS_PAYLOAD 0x0100
#define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE 0x0200 #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE 0x0200
#define V4L2_CTRL_FLAG_MODIFY_LAYOUT 0x0400 #define V4L2_CTRL_FLAG_MODIFY_LAYOUT 0x0400
#define V4L2_CTRL_FLAG_DYNAMIC_ARRAY 0x0800
/* Query flags, to be ORed with the control ID */ /* Query flags, to be ORed with the control ID */
#define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000 #define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000