Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 147 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/vidioc-g-edid.rst b/Documentation/media/uapi/v4l/vidioc-g-edid.rst
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_G_EDID:
+
+******************************************************************************
+ioctl VIDIOC_G_EDID, VIDIOC_S_EDID, VIDIOC_SUBDEV_G_EDID, VIDIOC_SUBDEV_S_EDID
+******************************************************************************
+
+Name
+====
+
+VIDIOC_G_EDID - VIDIOC_S_EDID - VIDIOC_SUBDEV_G_EDID - VIDIOC_SUBDEV_S_EDID - Get or set the EDID of a video receiver/transmitter
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, VIDIOC_G_EDID, struct v4l2_edid *argp )
+    :name: VIDIOC_G_EDID
+
+.. c:function:: int ioctl( int fd, VIDIOC_S_EDID, struct v4l2_edid *argp )
+    :name: VIDIOC_S_EDID
+
+
+.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_EDID, struct v4l2_edid *argp )
+    :name: VIDIOC_SUBDEV_G_EDID
+
+.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_EDID, struct v4l2_edid *argp )
+    :name: VIDIOC_SUBDEV_S_EDID
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``argp``
+   Pointer to struct :c:type:`v4l2_edid`.
+
+
+Description
+===========
+
+These ioctls can be used to get or set an EDID associated with an input
+from a receiver or an output of a transmitter device. They can be used
+with subdevice nodes (/dev/v4l-subdevX) or with video nodes
+(/dev/videoX).
+
+When used with video nodes the ``pad`` field represents the input (for
+video capture devices) or output (for video output devices) index as is
+returned by :ref:`VIDIOC_ENUMINPUT` and
+:ref:`VIDIOC_ENUMOUTPUT` respectively. When used
+with subdevice nodes the ``pad`` field represents the input or output
+pad of the subdevice. If there is no EDID support for the given ``pad``
+value, then the ``EINVAL`` error code will be returned.
+
+To get the EDID data the application has to fill in the ``pad``,
+``start_block``, ``blocks`` and ``edid`` fields, zero the ``reserved``
+array and call :ref:`VIDIOC_G_EDID <VIDIOC_G_EDID>`. The current EDID from block
+``start_block`` and of size ``blocks`` will be placed in the memory
+``edid`` points to. The ``edid`` pointer must point to memory at least
+``blocks`` * 128 bytes large (the size of one block is 128 bytes).
+
+If there are fewer blocks than specified, then the driver will set
+``blocks`` to the actual number of blocks. If there are no EDID blocks
+available at all, then the error code ``ENODATA`` is set.
+
+If blocks have to be retrieved from the sink, then this call will block
+until they have been read.
+
+If ``start_block`` and ``blocks`` are both set to 0 when
+:ref:`VIDIOC_G_EDID <VIDIOC_G_EDID>` is called, then the driver will set ``blocks`` to the
+total number of available EDID blocks and it will return 0 without
+copying any data. This is an easy way to discover how many EDID blocks
+there are.
+
+.. note::
+
+   If there are no EDID blocks available at all, then
+   the driver will set ``blocks`` to 0 and it returns 0.
+
+To set the EDID blocks of a receiver the application has to fill in the
+``pad``, ``blocks`` and ``edid`` fields, set ``start_block`` to 0 and
+zero the ``reserved`` array. It is not possible to set part of an EDID,
+it is always all or nothing. Setting the EDID data is only valid for
+receivers as it makes no sense for a transmitter.
+
+The driver assumes that the full EDID is passed in. If there are more
+EDID blocks than the hardware can handle then the EDID is not written,
+but instead the error code ``E2BIG`` is set and ``blocks`` is set to the
+maximum that the hardware supports. If ``start_block`` is any value
+other than 0 then the error code ``EINVAL`` is set.
+
+To disable an EDID you set ``blocks`` to 0. Depending on the hardware
+this will drive the hotplug pin low and/or block the source from reading
+the EDID data in some way. In any case, the end result is the same: the
+EDID is no longer available.
+
+
+.. c:type:: v4l2_edid
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct v4l2_edid
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u32
+      - ``pad``
+      - Pad for which to get/set the EDID blocks. When used with a video
+	device node the pad represents the input or output index as
+	returned by :ref:`VIDIOC_ENUMINPUT` and
+	:ref:`VIDIOC_ENUMOUTPUT` respectively.
+    * - __u32
+      - ``start_block``
+      - Read the EDID from starting with this block. Must be 0 when
+	setting the EDID.
+    * - __u32
+      - ``blocks``
+      - The number of blocks to get or set. Must be less or equal to 256
+	(the maximum number of blocks as defined by the standard). When
+	you set the EDID and ``blocks`` is 0, then the EDID is disabled or
+	erased.
+    * - __u32
+      - ``reserved``\ [5]
+      - Reserved for future extensions. Applications and drivers must set
+	the array to zero.
+    * - __u8 *
+      - ``edid``
+      - Pointer to memory that contains the EDID. The minimum size is
+	``blocks`` * 128.
+
+
+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.
+
+``ENODATA``
+    The EDID data is not available.
+
+``E2BIG``
+    The EDID data you provided is more than the hardware can handle.