150 lines
4.4 KiB
ReStructuredText
150 lines
4.4 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
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.. c:namespace:: V4L
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.. _VIDIOC_SUBDEV_G_ROUTING:
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******************************************************
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ioctl VIDIOC_SUBDEV_G_ROUTING, VIDIOC_SUBDEV_S_ROUTING
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******************************************************
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Name
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====
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VIDIOC_SUBDEV_G_ROUTING - VIDIOC_SUBDEV_S_ROUTING - Get or set routing between streams of media pads in a media entity.
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Synopsis
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========
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.. c:macro:: VIDIOC_SUBDEV_G_ROUTING
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``int ioctl(int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp)``
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.. c:macro:: VIDIOC_SUBDEV_S_ROUTING
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``int ioctl(int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp)``
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <func-open>`.
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``argp``
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Pointer to struct :c:type:`v4l2_subdev_routing`.
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Description
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===========
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These ioctls are used to get and set the routing in a media entity.
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The routing configuration determines the flows of data inside an entity.
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Drivers report their current routing tables using the
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``VIDIOC_SUBDEV_G_ROUTING`` ioctl and application may enable or disable routes
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with the ``VIDIOC_SUBDEV_S_ROUTING`` ioctl, by adding or removing routes and
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setting or clearing flags of the ``flags`` field of a
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struct :c:type:`v4l2_subdev_route`.
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All stream configurations are reset when ``VIDIOC_SUBDEV_S_ROUTING`` is called. This
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means that the userspace must reconfigure all streams after calling the ioctl
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with e.g. ``VIDIOC_SUBDEV_S_FMT``.
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Only subdevices which have both sink and source pads can support routing.
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When inspecting routes through ``VIDIOC_SUBDEV_G_ROUTING`` and the application
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provided ``num_routes`` is not big enough to contain all the available routes
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the subdevice exposes, drivers return the ENOSPC error code and adjust the
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value of the ``num_routes`` field. Application should then reserve enough memory
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for all the route entries and call ``VIDIOC_SUBDEV_G_ROUTING`` again.
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On a successful ``VIDIOC_SUBDEV_G_ROUTING`` call the driver updates the
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``num_routes`` field to reflect the actual number of routes returned.
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.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
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.. c:type:: v4l2_subdev_routing
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.. flat-table:: struct v4l2_subdev_routing
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:header-rows: 0
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:stub-columns: 0
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:widths: 1 1 2
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* - __u32
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- ``which``
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- Routing table to be accessed, from enum
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:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
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* - struct :c:type:`v4l2_subdev_route`
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- ``routes[]``
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- Array of struct :c:type:`v4l2_subdev_route` entries
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* - __u32
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- ``num_routes``
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- Number of entries of the routes array
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* - __u32
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- ``reserved``\ [5]
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- Reserved for future extensions. Applications and drivers must set
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the array to zero.
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.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
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.. c:type:: v4l2_subdev_route
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.. flat-table:: struct v4l2_subdev_route
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:header-rows: 0
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:stub-columns: 0
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:widths: 1 1 2
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* - __u32
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- ``sink_pad``
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- Sink pad number.
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* - __u32
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- ``sink_stream``
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- Sink pad stream number.
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* - __u32
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- ``source_pad``
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- Source pad number.
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* - __u32
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- ``source_stream``
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- Source pad stream number.
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* - __u32
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- ``flags``
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- Route enable/disable flags
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:ref:`v4l2_subdev_routing_flags <v4l2-subdev-routing-flags>`.
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* - __u32
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- ``reserved``\ [5]
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- Reserved for future extensions. Applications and drivers must set
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the array to zero.
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.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
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.. _v4l2-subdev-routing-flags:
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.. flat-table:: enum v4l2_subdev_routing_flags
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:header-rows: 0
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:stub-columns: 0
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:widths: 3 1 4
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* - V4L2_SUBDEV_ROUTE_FL_ACTIVE
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- 0x0001
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- The route is enabled. Set by applications.
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Return Value
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============
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On success 0 is returned, on error -1 and the ``errno`` variable is set
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appropriately. The generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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ENOSPC
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The application provided ``num_routes`` is not big enough to contain
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all the available routes the subdevice exposes.
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EINVAL
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The sink or source pad identifiers reference a non-existing pad or reference
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pads of different types (ie. the sink_pad identifiers refers to a source
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pad), or the ``which`` field has an unsupported value.
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E2BIG
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The application provided ``num_routes`` for ``VIDIOC_SUBDEV_S_ROUTING`` is
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larger than the number of routes the driver can handle.
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