ioctl VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL

&manvol;

VIDIOC_SUBDEV_G_FRAME_INTERVAL

VIDIOC_SUBDEV_S_FRAME_INTERVAL

Get or set the frame interval on a subdev pad

    	int ioctl
    	int fd
    	int request
    	struct v4l2_subdev_frame_interval *argp

## Arguments

`fd`

- &fd;

`request`

- VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL

`argp`

## Description

These ioctls are used to get and set the frame interval at specific subdev pads in the image pipeline. The frame interval only makes sense for sub-devices that can control the frame period on their own. This includes, for instance, image sensors and TV tuners. Sub-devices that don't support frame intervals must not implement these ioctls.

To retrieve the current frame interval applications set the pad field of a &v4l2-subdev-frame-interval; to the desired pad number as reported by the media controller API. When they call the `VIDIOC_SUBDEV_G_FRAME_INTERVAL` ioctl with a pointer to this structure the driver fills the members of the interval field.

To change the current frame interval applications set both the pad field and all members of the interval field. When they call the `VIDIOC_SUBDEV_S_FRAME_INTERVAL` ioctl with a pointer to this structure the driver verifies the requested interval, adjusts it based on the hardware capabilities and configures the device. Upon return the &v4l2-subdev-frame-interval; contains the current frame interval as would be returned by a `VIDIOC_SUBDEV_G_FRAME_INTERVAL` call.

Drivers must not return an error solely because the requested interval doesn't match the device capabilities. They must instead modify the interval to match what the hardware can provide. The modified interval should be as close as possible to the original request.

Sub-devices that support the frame interval ioctls should implement them on a single pad only. Their behaviour when supported on multiple pads of the same sub-device is not defined.

## struct v4l2_subdev_frame_interval

&cs-str;
__u32 | pad | Pad number as reported by the media controller API.
&v4l2-fract; | interval | Period, in seconds, between consecutive video frames.
__u32 | reserved[9] | Reserved for future extensions. Applications and drivers must set the array to zero.

&return-value;

EBUSY

- The frame interval can't be changed because the pad is currently busy. This can be caused, for instance, by an active video stream on the pad. The ioctl must not be retried without performing another action to fix the problem first. Only returned by `VIDIOC_SUBDEV_S_FRAME_INTERVAL`

EINVAL

- The &v4l2-subdev-frame-interval; pad references a non-existing pad, or the pad doesn't support frame intervals.