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| -rw-r--r-- | Documentation/media/uapi/dvb/dmx-qbuf.rst | 93 |
1 files changed, 0 insertions, 93 deletions
diff --git a/Documentation/media/uapi/dvb/dmx-qbuf.rst b/Documentation/media/uapi/dvb/dmx-qbuf.rst deleted file mode 100644 index 9dc845daa59d..000000000000 --- a/Documentation/media/uapi/dvb/dmx-qbuf.rst +++ /dev/null @@ -1,93 +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 - -.. _DMX_QBUF: - -************************* -ioctl DMX_QBUF, DMX_DQBUF -************************* - -Name -==== - -DMX_QBUF - DMX_DQBUF - Exchange a buffer with the driver - -.. warning:: this API is still experimental - - -Synopsis -======== - -.. c:function:: int ioctl( int fd, DMX_QBUF, struct dmx_buffer *argp ) - :name: DMX_QBUF - -.. c:function:: int ioctl( int fd, DMX_DQBUF, struct dmx_buffer *argp ) - :name: DMX_DQBUF - - -Arguments -========= - -``fd`` - File descriptor returned by :ref:`open() <dmx_fopen>`. - -``argp`` - Pointer to struct :c:type:`dmx_buffer`. - - -Description -=========== - -Applications call the ``DMX_QBUF`` ioctl to enqueue an empty -(capturing) or filled (output) buffer in the driver's incoming queue. -The semantics depend on the selected I/O method. - -To enqueue a buffer applications set the ``index`` field. Valid index -numbers range from zero to the number of buffers allocated with -:ref:`DMX_REQBUFS` (struct :c:type:`dmx_requestbuffers` ``count``) minus -one. The contents of the struct :c:type:`dmx_buffer` returned -by a :ref:`DMX_QUERYBUF` ioctl will do as well. - -When ``DMX_QBUF`` is called with a pointer to this structure, it locks the -memory pages of the buffer in physical memory, so they cannot be swapped -out to disk. Buffers remain locked until dequeued, until the -the device is closed. - -Applications call the ``DMX_DQBUF`` ioctl to dequeue a filled -(capturing) buffer from the driver's outgoing queue. -They just set the ``index`` field with the buffer ID to be queued. -When ``DMX_DQBUF`` is called with a pointer to struct :c:type:`dmx_buffer`, -the driver fills the remaining fields or returns an error code. - -By default ``DMX_DQBUF`` blocks when no buffer is in the outgoing -queue. When the ``O_NONBLOCK`` flag was given to the -:ref:`open() <dmx_fopen>` function, ``DMX_DQBUF`` returns -immediately with an ``EAGAIN`` error code when no buffer is available. - -The struct :c:type:`dmx_buffer` structure is specified in -:ref:`buffer`. - - -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. - -EAGAIN - Non-blocking I/O has been selected using ``O_NONBLOCK`` and no - buffer was in the outgoing queue. - -EINVAL - The ``index`` is out of bounds, or no buffers have been allocated yet. - -EIO - ``DMX_DQBUF`` failed due to an internal error. Can also indicate - temporary problems like signal loss or CRC errors. |