diff options
Diffstat (limited to 'Documentation/media/uapi/v4l/querycap.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/querycap.rst | 41 |
1 files changed, 0 insertions, 41 deletions
diff --git a/Documentation/media/uapi/v4l/querycap.rst b/Documentation/media/uapi/v4l/querycap.rst deleted file mode 100644 index 8d01ef52f780..000000000000 --- a/Documentation/media/uapi/v4l/querycap.rst +++ /dev/null @@ -1,41 +0,0 @@ -.. Permission is granted to copy, distribute and/or modify this -.. document under the terms of the GNU Free Documentation License, -.. Version 1.1 or any later version published by the Free Software -.. Foundation, with no Invariant Sections, no Front-Cover Texts -.. and no Back-Cover Texts. A copy of the license is included at -.. Documentation/media/uapi/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections - -.. _querycap: - -********************* -Querying Capabilities -********************* - -Because V4L2 covers a wide variety of devices not all aspects of the API -are equally applicable to all types of devices. Furthermore devices of -the same type have different capabilities and this specification permits -the omission of a few complicated and less important parts of the API. - -The :ref:`VIDIOC_QUERYCAP` ioctl is available to -check if the kernel device is compatible with this specification, and to -query the :ref:`functions <devices>` and :ref:`I/O methods <io>` -supported by the device. - -Starting with kernel version 3.1, :ref:`VIDIOC_QUERYCAP` -will return the V4L2 API version used by the driver, with generally -matches the Kernel version. There's no need of using -:ref:`VIDIOC_QUERYCAP` to check if a specific ioctl -is supported, the V4L2 core now returns ``ENOTTY`` if a driver doesn't -provide support for an ioctl. - -Other features can be queried by calling the respective ioctl, for -example :ref:`VIDIOC_ENUMINPUT` to learn about the -number, types and names of video connectors on the device. Although -abstraction is a major objective of this API, the -:ref:`VIDIOC_QUERYCAP` ioctl also allows driver -specific applications to reliably identify the driver. - -All V4L2 drivers must support :ref:`VIDIOC_QUERYCAP`. -Applications should always call this ioctl after opening the device. |