diff options
Diffstat (limited to 'Documentation/media/uapi/dvb/dmx-expbuf.rst')
| -rw-r--r-- | Documentation/media/uapi/dvb/dmx-expbuf.rst | 97 |
1 files changed, 0 insertions, 97 deletions
diff --git a/Documentation/media/uapi/dvb/dmx-expbuf.rst b/Documentation/media/uapi/dvb/dmx-expbuf.rst deleted file mode 100644 index d7f0658f3db3..000000000000 --- a/Documentation/media/uapi/dvb/dmx-expbuf.rst +++ /dev/null @@ -1,97 +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_EXPBUF: - -**************** -ioctl DMX_EXPBUF -**************** - -Name -==== - -DMX_EXPBUF - Export a buffer as a DMABUF file descriptor. - -.. warning:: this API is still experimental - - -Synopsis -======== - -.. c:function:: int ioctl( int fd, DMX_EXPBUF, struct dmx_exportbuffer *argp ) - :name: DMX_EXPBUF - - -Arguments -========= - -``fd`` - File descriptor returned by :ref:`open() <dmx_fopen>`. - -``argp`` - Pointer to struct :c:type:`dmx_exportbuffer`. - - -Description -=========== - -This ioctl is an extension to the memory mapping I/O method. -It can be used to export a buffer as a DMABUF file at any time after -buffers have been allocated with the :ref:`DMX_REQBUFS` ioctl. - -To export a buffer, applications fill struct :c:type:`dmx_exportbuffer`. -Applications must 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. -Additional flags may be posted in the ``flags`` field. Refer to a manual -for open() for details. Currently only O_CLOEXEC, O_RDONLY, O_WRONLY, -and O_RDWR are supported. -All other fields must be set to zero. In the -case of multi-planar API, every plane is exported separately using -multiple :ref:`DMX_EXPBUF` calls. - -After calling :ref:`DMX_EXPBUF` the ``fd`` field will be set by a -driver, on success. This is a DMABUF file descriptor. The application may -pass it to other DMABUF-aware devices. It is recommended to close a DMABUF -file when it is no longer used to allow the associated memory to be reclaimed. - - -Examples -======== - - -.. code-block:: c - - int buffer_export(int v4lfd, enum dmx_buf_type bt, int index, int *dmafd) - { - struct dmx_exportbuffer expbuf; - - memset(&expbuf, 0, sizeof(expbuf)); - expbuf.type = bt; - expbuf.index = index; - if (ioctl(v4lfd, DMX_EXPBUF, &expbuf) == -1) { - perror("DMX_EXPBUF"); - return -1; - } - - *dmafd = expbuf.fd; - - return 0; - } - -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. - -EINVAL - A queue is not in MMAP mode or DMABUF exporting is not supported or - ``flags`` or ``index`` fields are invalid. |