From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- Documentation/DocBook/media/v4l/vidioc-dqevent.xml | 468 +++++++++++++++++++++ 1 file changed, 468 insertions(+) create mode 100644 Documentation/DocBook/media/v4l/vidioc-dqevent.xml (limited to 'Documentation/DocBook/media/v4l/vidioc-dqevent.xml') diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml new file mode 100644 index 000000000..50ccd3394 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml @@ -0,0 +1,468 @@ + + + ioctl VIDIOC_DQEVENT + &manvol; + + + + VIDIOC_DQEVENT + Dequeue event + + + + + + int ioctl + int fd + int request + struct v4l2_event +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_DQEVENT + + + + argp + + + + + + + + + Description + + Dequeue an event from a video device. No input is required + for this ioctl. All the fields of the &v4l2-event; structure are + filled by the driver. The file handle will also receive exceptions + which the application may get by e.g. using the select system + call. + + + struct <structname>v4l2_event</structname> + + &cs-str; + + + __u32 + type + + Type of the event, see . + + + union + u + + + + + + &v4l2-event-vsync; + vsync + Event data for event V4L2_EVENT_VSYNC. + + + + + &v4l2-event-ctrl; + ctrl + Event data for event V4L2_EVENT_CTRL. + + + + + &v4l2-event-frame-sync; + frame_sync + Event data for event + V4L2_EVENT_FRAME_SYNC. + + + + &v4l2-event-motion-det; + motion_det + Event data for event V4L2_EVENT_MOTION_DET. + + + + &v4l2-event-src-change; + src_change + Event data for event V4L2_EVENT_SOURCE_CHANGE. + + + + __u8 + data[64] + Event data. Defined by the event type. The union + should be used to define easily accessible type for + events. + + + __u32 + pending + + Number of pending events excluding this one. + + + __u32 + sequence + + Event sequence number. The sequence number is + incremented for every subscribed event that takes place. + If sequence numbers are not contiguous it means that + events have been lost. + + + + struct timespec + timestamp + + Event timestamp. + + + u32 + id + + The ID associated with the event source. If the event does not + have an associated ID (this depends on the event type), then this + is 0. + + + __u32 + reserved[8] + + Reserved for future extensions. Drivers must set + the array to zero. + + + +
+ + + Event Types + + &cs-def; + + + V4L2_EVENT_ALL + 0 + All events. V4L2_EVENT_ALL is valid only for + VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once. + + + + V4L2_EVENT_VSYNC + 1 + This event is triggered on the vertical sync. + This event has a &v4l2-event-vsync; associated with it. + + + + V4L2_EVENT_EOS + 2 + This event is triggered when the end of a stream is reached. + This is typically used with MPEG decoders to report to the application + when the last of the MPEG stream has been decoded. + + + + V4L2_EVENT_CTRL + 3 + This event requires that the id + matches the control ID from which you want to receive events. + This event is triggered if the control's value changes, if a + button control is pressed or if the control's flags change. + This event has a &v4l2-event-ctrl; associated with it. This struct + contains much of the same information as &v4l2-queryctrl; and + &v4l2-control;. + + If the event is generated due to a call to &VIDIOC-S-CTRL; or + &VIDIOC-S-EXT-CTRLS;, then the event will not be sent to + the file handle that called the ioctl function. This prevents + nasty feedback loops. If you do want to get the + event, then set the V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK + flag. + + + This event type will ensure that no information is lost when + more events are raised than there is room internally. In that + case the &v4l2-event-ctrl; of the second-oldest event is kept, + but the changes field of the + second-oldest event is ORed with the changes + field of the oldest event. + + + + V4L2_EVENT_FRAME_SYNC + 4 + + Triggered immediately when the reception of a + frame has begun. This event has a + &v4l2-event-frame-sync; associated with it. + + If the hardware needs to be stopped in the case of a + buffer underrun it might not be able to generate this event. + In such cases the frame_sequence + field in &v4l2-event-frame-sync; will not be incremented. This + causes two consecutive frame sequence numbers to have n times + frame interval in between them. + + + + V4L2_EVENT_SOURCE_CHANGE + 5 + + This event is triggered when a source parameter change is + detected during runtime by the video device. It can be a + runtime resolution change triggered by a video decoder or the + format change happening on an input connector. + This event requires that the id + matches the input index (when used with a video device node) + or the pad index (when used with a subdevice node) from which + you want to receive events. + + This event has a &v4l2-event-src-change; associated + with it. The changes bitfield denotes + what has changed for the subscribed pad. If multiple events + occurred before application could dequeue them, then the changes + will have the ORed value of all the events generated. + + + + V4L2_EVENT_MOTION_DET + 6 + + Triggered whenever the motion detection state for one or more of the regions + changes. This event has a &v4l2-event-motion-det; associated with it. + + + + V4L2_EVENT_PRIVATE_START + 0x08000000 + Base event number for driver-private events. + + + +
+ + + struct <structname>v4l2_event_vsync</structname> + + &cs-str; + + + __u8 + field + The upcoming field. See &v4l2-field;. + + + +
+ + + struct <structname>v4l2_event_ctrl</structname> + + &cs-str; + + + __u32 + changes + + A bitmask that tells what has changed. See . + + + __u32 + type + + The type of the control. See &v4l2-ctrl-type;. + + + union (anonymous) + + + + + + + __s32 + value + The 32-bit value of the control for 32-bit control types. + This is 0 for string controls since the value of a string + cannot be passed using &VIDIOC-DQEVENT;. + + + + __s64 + value64 + The 64-bit value of the control for 64-bit control types. + + + __u32 + flags + + The control flags. See . + + + __s32 + minimum + + The minimum value of the control. See &v4l2-queryctrl;. + + + __s32 + maximum + + The maximum value of the control. See &v4l2-queryctrl;. + + + __s32 + step + + The step value of the control. See &v4l2-queryctrl;. + + + __s32 + default_value + + The default value value of the control. See &v4l2-queryctrl;. + + + +
+ + + struct <structname>v4l2_event_frame_sync</structname> + + &cs-str; + + + __u32 + frame_sequence + + The sequence number of the frame being received. + + + + +
+ + + struct <structname>v4l2_event_src_change</structname> + + &cs-str; + + + __u32 + changes + + A bitmask that tells what has changed. See . + + + + +
+ + + struct <structname>v4l2_event_motion_det</structname> + + &cs-str; + + + __u32 + flags + + Currently only one flag is available: if V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ + is set, then the frame_sequence field is valid, + otherwise that field should be ignored. + + + + __u32 + frame_sequence + + The sequence number of the frame being received. Only valid if the + V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ flag was set. + + + + __u32 + region_mask + + The bitmask of the regions that reported motion. There is at least one + region. If this field is 0, then no motion was detected at all. + If there is no V4L2_CID_DETECT_MD_REGION_GRID control + (see ) to assign a different region + to each cell in the motion detection grid, then that all cells + are automatically assigned to the default region 0. + + + + +
+ + + Control Changes + + &cs-def; + + + V4L2_EVENT_CTRL_CH_VALUE + 0x0001 + This control event was triggered because the value of the control + changed. Special cases: Volatile controls do no generate this event; + If a control has the V4L2_CTRL_FLAG_EXECUTE_ON_WRITE + flag set, then this event is sent as well, regardless its value. + + + V4L2_EVENT_CTRL_CH_FLAGS + 0x0002 + This control event was triggered because the control flags + changed. + + + V4L2_EVENT_CTRL_CH_RANGE + 0x0004 + This control event was triggered because the minimum, + maximum, step or the default value of the control changed. + + + +
+ + + Source Changes + + &cs-def; + + + V4L2_EVENT_SRC_CH_RESOLUTION + 0x0001 + This event gets triggered when a resolution change is + detected at an input. This can come from an input connector or + from a video decoder. + + + + +
+ + + &return-value; + + -- cgit v1.2.3-54-g00ecf