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diff --git a/Documentation/media/uapi/cec/cec-intro.rst b/Documentation/media/uapi/cec/cec-intro.rst deleted file mode 100644 index 05088fcefe81..000000000000 --- a/Documentation/media/uapi/cec/cec-intro.rst +++ /dev/null @@ -1,49 +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 - -.. _cec-intro: - -Introduction -============ - -HDMI connectors provide a single pin for use by the Consumer Electronics -Control protocol. This protocol allows different devices connected by an -HDMI cable to communicate. The protocol for CEC version 1.4 is defined -in supplements 1 (CEC) and 2 (HEAC or HDMI Ethernet and Audio Return -Channel) of the HDMI 1.4a (:ref:`hdmi`) specification and the -extensions added to CEC version 2.0 are defined in chapter 11 of the -HDMI 2.0 (:ref:`hdmi2`) specification. - -The bitrate is very slow (effectively no more than 36 bytes per second) -and is based on the ancient AV.link protocol used in old SCART -connectors. The protocol closely resembles a crazy Rube Goldberg -contraption and is an unholy mix of low and high level messages. Some -messages, especially those part of the HEAC protocol layered on top of -CEC, need to be handled by the kernel, others can be handled either by -the kernel or by userspace. - -In addition, CEC can be implemented in HDMI receivers, transmitters and -in USB devices that have an HDMI input and an HDMI output and that -control just the CEC pin. - -Drivers that support CEC will create a CEC device node (/dev/cecX) to -give userspace access to the CEC adapter. The -:ref:`CEC_ADAP_G_CAPS` ioctl will tell userspace what it is allowed to do. - -In order to check the support and test it, it is suggested to download -the `v4l-utils <https://git.linuxtv.org/v4l-utils.git/>`_ package. It -provides three tools to handle CEC: - -- cec-ctl: the Swiss army knife of CEC. Allows you to configure, transmit - and monitor CEC messages. - -- cec-compliance: does a CEC compliance test of a remote CEC device to - determine how compliant the CEC implementation is. - -- cec-follower: emulates a CEC follower. |