summaryrefslogtreecommitdiff
path: root/Documentation/media/uapi/v4l/vidioc-subscribe-event.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-subscribe-event.rst')
-rw-r--r--Documentation/media/uapi/v4l/vidioc-subscribe-event.rst120
1 files changed, 45 insertions, 75 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-subscribe-event.rst b/Documentation/media/uapi/v4l/vidioc-subscribe-event.rst
index 0202a78cbeb0..e4a51431032c 100644
--- a/Documentation/media/uapi/v4l/vidioc-subscribe-event.rst
+++ b/Documentation/media/uapi/v4l/vidioc-subscribe-event.rst
@@ -48,47 +48,27 @@ using the :ref:`VIDIOC_DQEVENT` ioctl.
:stub-columns: 0
:widths: 1 1 2
-
- - .. row 1
-
- - __u32
-
- - ``type``
-
- - Type of the event, see :ref:`event-type`.
-
- .. note::
-
- ``V4L2_EVENT_ALL`` can be used with
- :ref:`VIDIOC_UNSUBSCRIBE_EVENT <VIDIOC_SUBSCRIBE_EVENT>` for
- unsubscribing all events at once.
-
- - .. row 2
-
- - __u32
-
- - ``id``
-
- - ID of the event source. If there is no ID associated with the
- event source, then set this to 0. Whether or not an event needs an
- ID depends on the event type.
-
- - .. row 3
-
- - __u32
-
- - ``flags``
-
- - Event flags, see :ref:`event-flags`.
-
- - .. row 4
-
- - __u32
-
- - ``reserved``\ [5]
-
- - Reserved for future extensions. Drivers and applications must set
- the array to zero.
+ * - __u32
+ - ``type``
+ - Type of the event, see :ref:`event-type`.
+
+ .. note::
+
+ ``V4L2_EVENT_ALL`` can be used with
+ :ref:`VIDIOC_UNSUBSCRIBE_EVENT <VIDIOC_SUBSCRIBE_EVENT>` for
+ unsubscribing all events at once.
+ * - __u32
+ - ``id``
+ - ID of the event source. If there is no ID associated with the
+ event source, then set this to 0. Whether or not an event needs an
+ ID depends on the event type.
+ * - __u32
+ - ``flags``
+ - Event flags, see :ref:`event-flags`.
+ * - __u32
+ - ``reserved``\ [5]
+ - Reserved for future extensions. Drivers and applications must set
+ the array to zero.
@@ -101,40 +81,30 @@ using the :ref:`VIDIOC_DQEVENT` ioctl.
:stub-columns: 0
:widths: 3 1 4
-
- - .. row 1
-
- - ``V4L2_EVENT_SUB_FL_SEND_INITIAL``
-
- - 0x0001
-
- - When this event is subscribed an initial event will be sent
- containing the current status. This only makes sense for events
- that are triggered by a status change such as ``V4L2_EVENT_CTRL``.
- Other events will ignore this flag.
-
- - .. row 2
-
- - ``V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK``
-
- - 0x0002
-
- - If set, then events directly caused by an ioctl will also be sent
- to the filehandle that called that ioctl. For example, changing a
- control using :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` will cause
- a V4L2_EVENT_CTRL to be sent back to that same filehandle.
- Normally such events are suppressed to prevent feedback loops
- where an application changes a control to a one value and then
- another, and then receives an event telling it that that control
- has changed to the first value.
-
- Since it can't tell whether that event was caused by another
- application or by the :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>`
- call it is hard to decide whether to set the control to the value
- in the event, or ignore it.
-
- Think carefully when you set this flag so you won't get into
- situations like that.
+ * - ``V4L2_EVENT_SUB_FL_SEND_INITIAL``
+ - 0x0001
+ - When this event is subscribed an initial event will be sent
+ containing the current status. This only makes sense for events
+ that are triggered by a status change such as ``V4L2_EVENT_CTRL``.
+ Other events will ignore this flag.
+ * - ``V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK``
+ - 0x0002
+ - If set, then events directly caused by an ioctl will also be sent
+ to the filehandle that called that ioctl. For example, changing a
+ control using :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` will cause
+ a V4L2_EVENT_CTRL to be sent back to that same filehandle.
+ Normally such events are suppressed to prevent feedback loops
+ where an application changes a control to a one value and then
+ another, and then receives an event telling it that that control
+ has changed to the first value.
+
+ Since it can't tell whether that event was caused by another
+ application or by the :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>`
+ call it is hard to decide whether to set the control to the value
+ in the event, or ignore it.
+
+ Think carefully when you set this flag so you won't get into
+ situations like that.
Return Value