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author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-27 16:45:04 +0300 |
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committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-27 16:45:04 +0300 |
commit | 85538b1ad145c67198cb55d02de14ba269cc323d (patch) | |
tree | 409fca93b357839b8c89b7099f2888c087694b64 /Documentation/media/uapi/v4l/vidioc-g-output.rst | |
parent | 9c1958fc326a0a0a533ec8e86ea6fa30977207de (diff) | |
parent | d271d3d9b333c94cd54a12fa506e17772a04617c (diff) | |
download | linux-85538b1ad145c67198cb55d02de14ba269cc323d.tar.xz |
Merge branch 'topic/docs-next' into v4l_for_linus
* topic/docs-next: (322 commits)
[media] cx23885-cardlist.rst: add a new card
[media] doc-rst: add some needed escape codes
[media] doc-rst: kapi: use :c:func: instead of :cpp:func
doc-rst: kernel-doc: fix a change introduced by mistake
[media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops
[media] dvb_ringbuffer.h: some documentation improvements
[media] v4l2-ctrls.h: fully document the header file
[media] doc-rst: Fix some typedef ugly warnings
[media] doc-rst: reorganize the kAPI v4l2 chapters
[media] rename v4l2-framework.rst to v4l2-intro.rst
[media] move V4L2 clocks to a separate .rst file
[media] v4l2-fh.rst: add cross references and markups
[media] v4l2-fh.rst: add fh contents from v4l2-framework.rst
[media] v4l2-fh.h: add documentation for it
[media] v4l2-event.rst: add cross-references and markups
[media] v4l2-event.h: document all functions
[media] v4l2-event.rst: add text from v4l2-framework.rst
[media] v4l2-framework.rst: remove videobuf quick chapter
[media] v4l2-dev: add cross-references and improve markup
[media] doc-rst: move v4l2-dev doc to a separate file
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Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-g-output.rst')
-rw-r--r-- | Documentation/media/uapi/v4l/vidioc-g-output.rst | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-g-output.rst b/Documentation/media/uapi/v4l/vidioc-g-output.rst new file mode 100644 index 000000000000..ae0ad577ba97 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-g-output.rst @@ -0,0 +1,64 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_G_OUTPUT: + +************************************** +ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT +************************************** + +Name +==== + +VIDIOC_G_OUTPUT - VIDIOC_S_OUTPUT - Query or select the current video output + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, int *argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``request`` + VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT + +``argp`` + + +Description +=========== + +To query the current video output applications call the +:ref:`VIDIOC_G_OUTPUT <VIDIOC_G_OUTPUT>` ioctl with a pointer to an integer where the driver +stores the number of the output, as in the struct +:ref:`v4l2_output <v4l2-output>` ``index`` field. This ioctl will +fail only when there are no video outputs, returning the ``EINVAL`` error +code. + +To select a video output applications store the number of the desired +output in an integer and call the :ref:`VIDIOC_S_OUTPUT <VIDIOC_G_OUTPUT>` ioctl with a +pointer to this integer. Side effects are possible. For example outputs +may support different video standards, so the driver may implicitly +switch the current standard. standard. Because of these possible side +effects applications must select an output before querying or +negotiating any other parameters. + +Information about video outputs is available using the +:ref:`VIDIOC_ENUMOUTPUT` ioctl. + + +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 + The number of the video output is out of bounds, or there are no + video outputs at all. |