On 12/17/2015 09:40 AM, Laurent Pinchart wrote:
> Let userspace specify a request ID when getting or setting formats or
> selection rectangles.
>
> From a userspace point of view the API change is minimized and doesn't
> require any new ioctl.
>
> Signed-off-by: Laurent Pinchart <[email protected]>
> ---
> include/uapi/linux/v4l2-subdev.h | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/v4l2-subdev.h
> b/include/uapi/linux/v4l2-subdev.h
> index dbce2b554e02..2f1691ce9df5 100644
> --- a/include/uapi/linux/v4l2-subdev.h
> +++ b/include/uapi/linux/v4l2-subdev.h
> @@ -32,10 +32,12 @@
> * enum v4l2_subdev_format_whence - Media bus format type
> * @V4L2_SUBDEV_FORMAT_TRY: try format, for negotiation only
> * @V4L2_SUBDEV_FORMAT_ACTIVE: active format, applied to the device
> + * @V4L2_SUBDEV_FORMAT_REQUEST: format stored in request
> */
> enum v4l2_subdev_format_whence {
> V4L2_SUBDEV_FORMAT_TRY = 0,
> V4L2_SUBDEV_FORMAT_ACTIVE = 1,
> + V4L2_SUBDEV_FORMAT_REQUEST = 2,
> };
>
> /**
> @@ -43,12 +45,17 @@ enum v4l2_subdev_format_whence {
> * @which: format type (from enum v4l2_subdev_format_whence)
> * @pad: pad number, as reported by the media API
> * @format: media bus format (format code and frame size)
> + * @request: request ID (when which is set to V4L2_SUBDEV_FORMAT_REQUEST)
> + * @reserved2: for future use, set to zero for now
> + * @reserved: for future use, set to zero for now
> */
> struct v4l2_subdev_format {
> __u32 which;
> __u32 pad;
> struct v4l2_mbus_framefmt format;
> - __u32 reserved[8];
> + __u16 request;
> + __u16 reserved2;
> + __u32 reserved[7];
I would prefer:
__u16 request;
__u16 reserved[15];
> };
>
> /**
> @@ -139,6 +146,8 @@ struct v4l2_subdev_frame_interval_enum {
> * defined in v4l2-common.h; V4L2_SEL_TGT_* .
> * @flags: constraint flags, defined in v4l2-common.h; V4L2_SEL_FLAG_*.
> * @r: coordinates of the selection window
> + * @request: request ID (when which is set to V4L2_SUBDEV_FORMAT_REQUEST)
> + * @reserved2: for future use, set to zero for now
> * @reserved: for future use, set to zero for now
> *
> * Hardware may use multiple helper windows to process a video stream.
> @@ -151,7 +160,9 @@ struct v4l2_subdev_selection {
> __u32 target;
> __u32 flags;
> struct v4l2_rect r;
> - __u32 reserved[8];
> + __u16 request;
> + __u16 reserved2;
> + __u32 reserved[7];
Ditto.
Generally apps do a memset of reserved, and that will just keep working.
But adding a reserved2 field means that they have to explicitly set reserved2
to 0, which won't happen.
> };
>
> /* Backwards compatibility define --- to be removed */
>
Regards,
Hans
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