diff options
author | Jens Axboe <axboe@kernel.dk> | 2018-02-07 15:54:20 -0700 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2018-02-07 15:54:20 -0700 |
commit | 61a695184fcc8f225327206b88320279dd8684af (patch) | |
tree | 6cbda2b0e7de94ebad95072d17cc0aa82c9d8ab3 /Documentation/media/uapi/dvb/dmx-querybuf.rst | |
parent | 9e05c864993c5442227f83ae1694a737d7a102ed (diff) | |
parent | 581e400ff935d34d95811258586128bf11baef15 (diff) |
Merge branch 'master' into test
* master: (1190 commits)
ASoC: stm32: add of dependency for stm32 drivers
ASoC: mt8173-rt5650: fix child-node lookup
ASoC: dapm: fix debugfs read using path->connected
platform/x86: samsung-laptop: Re-use DEFINE_SHOW_ATTRIBUTE() macro
platform/x86: ideapad-laptop: Re-use DEFINE_SHOW_ATTRIBUTE() macro
platform/x86: dell-laptop: Re-use DEFINE_SHOW_ATTRIBUTE() macro
seq_file: Introduce DEFINE_SHOW_ATTRIBUTE() helper macro
Documentation/sysctl/user.txt: fix typo
MAINTAINERS: update ARM/QUALCOMM SUPPORT patterns
MAINTAINERS: update various PALM patterns
MAINTAINERS: update "ARM/OXNAS platform support" patterns
MAINTAINERS: update Cortina/Gemini patterns
MAINTAINERS: remove ARM/CLKDEV SUPPORT file pattern
MAINTAINERS: remove ANDROID ION pattern
mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors
mm: docs: fix parameter names mismatch
mm: docs: fixup punctuation
pipe: read buffer limits atomically
pipe: simplify round_pipe_size()
pipe: reject F_SETPIPE_SZ with size over UINT_MAX
...
Diffstat (limited to 'Documentation/media/uapi/dvb/dmx-querybuf.rst')
-rw-r--r-- | Documentation/media/uapi/dvb/dmx-querybuf.rst | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/Documentation/media/uapi/dvb/dmx-querybuf.rst b/Documentation/media/uapi/dvb/dmx-querybuf.rst new file mode 100644 index 000000000000..89481e24bb86 --- /dev/null +++ b/Documentation/media/uapi/dvb/dmx-querybuf.rst @@ -0,0 +1,63 @@ +.. _DMX_QUERYBUF: + +****************** +ioctl DMX_QUERYBUF +****************** + +Name +==== + +DMX_QUERYBUF - Query the status of a buffer + +.. warning:: this API is still experimental + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, DMX_QUERYBUF, struct dvb_buffer *argp ) + :name: DMX_QUERYBUF + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <dmx_fopen>`. + +``argp`` + Pointer to struct :c:type:`dvb_buffer`. + + +Description +=========== + +This ioctl is part of the mmap streaming I/O method. It can +be used to query the status of a buffer at any time after buffers have +been allocated with the :ref:`DMX_REQBUFS` ioctl. + +Applications set the ``index`` field. Valid index numbers range from zero +to the number of buffers allocated with :ref:`DMX_REQBUFS` +(struct :c:type:`dvb_requestbuffers` ``count``) minus one. + +After calling :ref:`DMX_QUERYBUF` with a pointer to this structure, +drivers return an error code or fill the rest of the structure. + +On success, the ``offset`` will contain the offset of the buffer from the +start of the device memory, the ``length`` field its size, and the +``bytesused`` the number of bytes occupied by data in the buffer (payload). + +Return Value +============ + +On success 0 is returned, the ``offset`` will contain the offset of the +buffer from the start of the device memory, the ``length`` field its size, +and the ``bytesused`` the number of bytes occupied by data in the buffer +(payload). + +On error it returns -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. + +EINVAL + The ``index`` is out of bounds. |