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diff --git a/Documentation/media/uapi/v4l/app-pri.rst b/Documentation/media/uapi/v4l/app-pri.rst deleted file mode 100644 index c25c1271b4f6..000000000000 --- a/Documentation/media/uapi/v4l/app-pri.rst +++ /dev/null @@ -1,37 +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 - -.. _app-pri: - -******************** -Application Priority -******************** - -When multiple applications share a device it may be desirable to assign -them different priorities. Contrary to the traditional "rm -rf /" school -of thought, a video recording application could for example block other -applications from changing video controls or switching the current TV -channel. Another objective is to permit low priority applications -working in background, which can be preempted by user controlled -applications and automatically regain control of the device at a later -time. - -Since these features cannot be implemented entirely in user space V4L2 -defines the :ref:`VIDIOC_G_PRIORITY <VIDIOC_G_PRIORITY>` and -:ref:`VIDIOC_S_PRIORITY <VIDIOC_G_PRIORITY>` ioctls to request and -query the access priority associate with a file descriptor. Opening a -device assigns a medium priority, compatible with earlier versions of -V4L2 and drivers not supporting these ioctls. Applications requiring a -different priority will usually call :ref:`VIDIOC_S_PRIORITY -<VIDIOC_G_PRIORITY>` after verifying the device with the -:ref:`VIDIOC_QUERYCAP` ioctl. - -Ioctls changing driver properties, such as -:ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>`, return an ``EBUSY`` error code -after another application obtained higher priority. |