7.61. ioctl VIDIOC_SUBDEV_G_ROUTING, VIDIOC_SUBDEV_S_ROUTING

7.61.1. Name

VIDIOC_SUBDEV_G_ROUTING - VIDIOC_SUBDEV_S_ROUTING - Get or set routing between streams of media pads in a media entity.

7.61.2. Synopsis

VIDIOC_SUBDEV_G_ROUTING

int ioctl(int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp)

VIDIOC_SUBDEV_S_ROUTING

int ioctl(int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp)

7.61.3. Arguments

fd

File descriptor returned by open().

argp

Pointer to struct v4l2_subdev_routing.

7.61.4. Description

These ioctls are used to get and set the routing in a media entity. The routing configuration determines the flows of data inside an entity.

Drivers report their current routing tables using the VIDIOC_SUBDEV_G_ROUTING ioctl and application may enable or disable routes with the VIDIOC_SUBDEV_S_ROUTING ioctl, by adding or removing routes and setting or clearing flags of the flags field of a struct v4l2_subdev_route.

All stream configurations are reset when VIDIOC_SUBDEV_S_ROUTING is called. This means that the userspace must reconfigure all streams after calling the ioctl with e.g. VIDIOC_SUBDEV_S_FMT.

Only subdevices which have both sink and source pads can support routing.

When inspecting routes through VIDIOC_SUBDEV_G_ROUTING and the application provided num_routes is not big enough to contain all the available routes the subdevice exposes, drivers return the ENOSPC error code and adjust the value of the num_routes field. Application should then reserve enough memory for all the route entries and call VIDIOC_SUBDEV_G_ROUTING again.

On a successful VIDIOC_SUBDEV_G_ROUTING call the driver updates the num_routes field to reflect the actual number of routes returned.

v4l2_subdev_routing

struct v4l2_subdev_routing

__u32	which	Format to modified, from enum v4l2_subdev_format_whence.
struct v4l2_subdev_route	routes[]	Array of struct v4l2_subdev_route entries
__u32	num_routes	Number of entries of the routes array
__u32	reserved[5]	Reserved for future extensions. Applications and drivers must set the array to zero.

v4l2_subdev_route

struct v4l2_subdev_route

__u32	sink_pad	Sink pad number.
__u32	sink_stream	Sink pad stream number.
__u32	source_pad	Source pad number.
__u32	source_stream	Source pad stream number.
__u32	flags	Route enable/disable flags v4l2_subdev_routing_flags.
__u32	reserved[5]	Reserved for future extensions. Applications and drivers must set the array to zero.

enum v4l2_subdev_routing_flags

V4L2_SUBDEV_ROUTE_FL_ACTIVE

0x0001

The route is enabled. Set by applications.

7.61.5. Return Value

On success 0 is returned, on error -1 and the errno variable is set appropriately. The generic error codes are described at the Generic Error Codes chapter.

ENOSPC

The application provided num_routes is not big enough to contain all the available routes the subdevice exposes.

EINVAL

The sink or source pad identifiers reference a non-existing pad, or reference pads of different types (ie. the sink_pad identifiers refers to a source pad).

E2BIG

The application provided num_routes for VIDIOC_SUBDEV_S_ROUTING is larger than the number of routes the driver can handle.