From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- .../userspace-api/media/dvb/dmx-querybuf.rst | 64 ++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 Documentation/userspace-api/media/dvb/dmx-querybuf.rst (limited to 'Documentation/userspace-api/media/dvb/dmx-querybuf.rst') diff --git a/Documentation/userspace-api/media/dvb/dmx-querybuf.rst b/Documentation/userspace-api/media/dvb/dmx-querybuf.rst new file mode 100644 index 000000000..08ee9853d --- /dev/null +++ b/Documentation/userspace-api/media/dvb/dmx-querybuf.rst @@ -0,0 +1,64 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: DTV.dmx + +.. _DMX_QUERYBUF: + +****************** +ioctl DMX_QUERYBUF +****************** + +Name +==== + +DMX_QUERYBUF - Query the status of a buffer + +.. warning:: this API is still experimental + +Synopsis +======== + +.. c:macro:: DMX_QUERYBUF + +``int ioctl(int fd, DMX_QUERYBUF, struct dvb_buffer *argp)`` + +Arguments +========= + +``fd`` + File descriptor returned by :c:func:`open()`. + +``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 ` chapter. + +EINVAL + The ``index`` is out of bounds. -- cgit v1.2.3