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diff --git a/Documentation/media/uapi/mediactl/media-controller-intro.rst b/Documentation/media/uapi/mediactl/media-controller-intro.rst deleted file mode 100644 index 281c559c2f3c..000000000000 --- a/Documentation/media/uapi/mediactl/media-controller-intro.rst +++ /dev/null @@ -1,40 +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 - -.. _media-controller-intro: - -Introduction -============ - -Media devices increasingly handle multiple related functions. Many USB -cameras include microphones, video capture hardware can also output -video, or SoC camera interfaces also perform memory-to-memory operations -similar to video codecs. - -Independent functions, even when implemented in the same hardware, can -be modelled as separate devices. A USB camera with a microphone will be -presented to userspace applications as V4L2 and ALSA capture devices. -The devices' relationships (when using a webcam, end-users shouldn't -have to manually select the associated USB microphone), while not made -available directly to applications by the drivers, can usually be -retrieved from sysfs. - -With more and more advanced SoC devices being introduced, the current -approach will not scale. Device topologies are getting increasingly -complex and can't always be represented by a tree structure. Hardware -blocks are shared between different functions, creating dependencies -between seemingly unrelated devices. - -Kernel abstraction APIs such as V4L2 and ALSA provide means for -applications to access hardware parameters. As newer hardware expose an -increasingly high number of those parameters, drivers need to guess what -applications really require based on limited information, thereby -implementing policies that belong to userspace. - -The media controller API aims at solving those problems. |