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.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
.. c:namespace:: V4L
.. _VIDIOC_SUBDEV_G_ROUTING:
******************************************************
ioctl VIDIOC_SUBDEV_G_ROUTING, VIDIOC_SUBDEV_S_ROUTING
******************************************************
Name
====
VIDIOC_SUBDEV_G_ROUTING - VIDIOC_SUBDEV_S_ROUTING - Get or set routing between streams of media pads in a media entity.
Synopsis
========
.. c:macro:: VIDIOC_SUBDEV_G_ROUTING
``int ioctl(int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp)``
.. c:macro:: VIDIOC_SUBDEV_S_ROUTING
``int ioctl(int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp)``
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
``argp``
Pointer to struct :c:type:`v4l2_subdev_routing`.
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 :c:type:`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.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
.. c:type:: v4l2_subdev_routing
.. flat-table:: struct v4l2_subdev_routing
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
* - __u32
- ``which``
- Routing table to be accessed, from enum
:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
* - struct :c:type:`v4l2_subdev_route`
- ``routes[]``
- Array of struct :c:type:`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.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
.. c:type:: v4l2_subdev_route
.. flat-table:: struct v4l2_subdev_route
:header-rows: 0
:stub-columns: 0
:widths: 1 1 2
* - __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
:ref:`v4l2_subdev_routing_flags <v4l2-subdev-routing-flags>`.
* - __u32
- ``reserved``\ [5]
- Reserved for future extensions. Applications and drivers must set
the array to zero.
.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
.. _v4l2-subdev-routing-flags:
.. flat-table:: enum v4l2_subdev_routing_flags
:header-rows: 0
:stub-columns: 0
:widths: 3 1 4
* - V4L2_SUBDEV_ROUTE_FL_ACTIVE
- 0x0001
- The route is enabled. Set by applications.
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
:ref:`Generic Error Codes <gen-errors>` 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), or the ``which`` field has an unsupported value.
E2BIG
The application provided ``num_routes`` for ``VIDIOC_SUBDEV_S_ROUTING`` is
larger than the number of routes the driver can handle.
|
