| Message ID | 20220628120523.2915913-2-hverkuil-cisco@xs4all.nl |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add dynamic arrays and v4l2_ctrl_modify_dimensions | expand |
Hi Hans, Thank you for the patch. On Tue, Jun 28, 2022 at 02:05:16PM +0200, Hans Verkuil wrote: > 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. > > Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> > Acked-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> > Tested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> > --- > .../userspace-api/media/v4l/vidioc-queryctrl.rst | 8 ++++++++ > .../userspace-api/media/videodev2.h.rst.exceptions | 1 + > include/uapi/linux/videodev2.h | 1 + > 3 files changed, 10 insertions(+) > > 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 > ============ > diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions > index 9cbb7a0c354a..0b91200776f8 100644 > --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions > +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions > @@ -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_EXECUTE_ON_WRITE 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_COMPOUND control > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h > index 5311ac4fde35..9018aa984db3 100644 > --- a/include/uapi/linux/videodev2.h > +++ b/include/uapi/linux/videodev2.h > @@ -1890,6 +1890,7 @@ struct v4l2_querymenu { > #define V4L2_CTRL_FLAG_HAS_PAYLOAD 0x0100 > #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE 0x0200 > #define V4L2_CTRL_FLAG_MODIFY_LAYOUT 0x0400 > +#define V4L2_CTRL_FLAG_DYNAMIC_ARRAY 0x0800 > > /* Query flags, to be ORed with the control ID */ > #define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000
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 ============ diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions index 9cbb7a0c354a..0b91200776f8 100644 --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions @@ -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_EXECUTE_ON_WRITE 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_COMPOUND control diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 5311ac4fde35..9018aa984db3 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -1890,6 +1890,7 @@ struct v4l2_querymenu { #define V4L2_CTRL_FLAG_HAS_PAYLOAD 0x0100 #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE 0x0200 #define V4L2_CTRL_FLAG_MODIFY_LAYOUT 0x0400 +#define V4L2_CTRL_FLAG_DYNAMIC_ARRAY 0x0800 /* Query flags, to be ORed with the control ID */ #define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000