1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: V4L 3 4.. _VIDIOC_SUBDEV_G_ROUTING: 5 6****************************************************** 7ioctl VIDIOC_SUBDEV_G_ROUTING, VIDIOC_SUBDEV_S_ROUTING 8****************************************************** 9 10Name 11==== 12 13VIDIOC_SUBDEV_G_ROUTING - VIDIOC_SUBDEV_S_ROUTING - Get or set routing between streams of media pads in a media entity. 14 15 16Synopsis 17======== 18 19.. c:macro:: VIDIOC_SUBDEV_G_ROUTING 20 21``int ioctl(int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp)`` 22 23.. c:macro:: VIDIOC_SUBDEV_S_ROUTING 24 25``int ioctl(int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp)`` 26 27Arguments 28========= 29 30``fd`` 31 File descriptor returned by :ref:`open() <func-open>`. 32 33``argp`` 34 Pointer to struct :c:type:`v4l2_subdev_routing`. 35 36 37Description 38=========== 39 40These ioctls are used to get and set the routing in a media entity. 41The routing configuration determines the flows of data inside an entity. 42 43Drivers report their current routing tables using the 44``VIDIOC_SUBDEV_G_ROUTING`` ioctl and application may enable or disable routes 45with the ``VIDIOC_SUBDEV_S_ROUTING`` ioctl, by adding or removing routes and 46setting or clearing flags of the ``flags`` field of a 47struct :c:type:`v4l2_subdev_route`. 48 49All stream configurations are reset when ``VIDIOC_SUBDEV_S_ROUTING`` is called. This 50means that the userspace must reconfigure all streams after calling the ioctl 51with e.g. ``VIDIOC_SUBDEV_S_FMT``. 52 53Only subdevices which have both sink and source pads can support routing. 54 55When inspecting routes through ``VIDIOC_SUBDEV_G_ROUTING`` and the application 56provided ``num_routes`` is not big enough to contain all the available routes 57the subdevice exposes, drivers return the ENOSPC error code and adjust the 58value of the ``num_routes`` field. Application should then reserve enough memory 59for all the route entries and call ``VIDIOC_SUBDEV_G_ROUTING`` again. 60 61On a successful ``VIDIOC_SUBDEV_G_ROUTING`` call the driver updates the 62``num_routes`` field to reflect the actual number of routes returned. 63 64.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 65 66.. c:type:: v4l2_subdev_routing 67 68.. flat-table:: struct v4l2_subdev_routing 69 :header-rows: 0 70 :stub-columns: 0 71 :widths: 1 1 2 72 73 * - __u32 74 - ``which`` 75 - Format to modified, from enum 76 :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. 77 * - struct :c:type:`v4l2_subdev_route` 78 - ``routes[]`` 79 - Array of struct :c:type:`v4l2_subdev_route` entries 80 * - __u32 81 - ``num_routes`` 82 - Number of entries of the routes array 83 * - __u32 84 - ``reserved``\ [5] 85 - Reserved for future extensions. Applications and drivers must set 86 the array to zero. 87 88.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| 89 90.. c:type:: v4l2_subdev_route 91 92.. flat-table:: struct v4l2_subdev_route 93 :header-rows: 0 94 :stub-columns: 0 95 :widths: 1 1 2 96 97 * - __u32 98 - ``sink_pad`` 99 - Sink pad number. 100 * - __u32 101 - ``sink_stream`` 102 - Sink pad stream number. 103 * - __u32 104 - ``source_pad`` 105 - Source pad number. 106 * - __u32 107 - ``source_stream`` 108 - Source pad stream number. 109 * - __u32 110 - ``flags`` 111 - Route enable/disable flags 112 :ref:`v4l2_subdev_routing_flags <v4l2-subdev-routing-flags>`. 113 * - __u32 114 - ``reserved``\ [5] 115 - Reserved for future extensions. Applications and drivers must set 116 the array to zero. 117 118.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| 119 120.. _v4l2-subdev-routing-flags: 121 122.. flat-table:: enum v4l2_subdev_routing_flags 123 :header-rows: 0 124 :stub-columns: 0 125 :widths: 3 1 4 126 127 * - V4L2_SUBDEV_ROUTE_FL_ACTIVE 128 - 0x0001 129 - The route is enabled. Set by applications. 130 131Return Value 132============ 133 134On success 0 is returned, on error -1 and the ``errno`` variable is set 135appropriately. The generic error codes are described at the 136:ref:`Generic Error Codes <gen-errors>` chapter. 137 138ENOSPC 139 The application provided ``num_routes`` is not big enough to contain 140 all the available routes the subdevice exposes. 141 142EINVAL 143 The sink or source pad identifiers reference a non-existing pad, or reference 144 pads of different types (ie. the sink_pad identifiers refers to a source pad). 145 146E2BIG 147 The application provided ``num_routes`` for ``VIDIOC_SUBDEV_S_ROUTING`` is 148 larger than the number of routes the driver can handle. 149