From 85724983c4d212c24116d45f6585a1c4ff845dd3 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Tue, 7 Jun 2011 09:53:37 -0300 Subject: [PATCH] [media] V4L2 spec: document control events Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- .../DocBook/media/v4l/vidioc-dqevent.xml | 17 ++- .../media/v4l/vidioc-subscribe-event.xml | 142 +++++++++++++++++- 2 files changed, 157 insertions(+), 2 deletions(-) diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml index 4e0a7cc30812..b8c4f7657d69 100644 --- a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml @@ -79,6 +79,13 @@ Event data for event V4L2_EVENT_VSYNC. + + + &v4l2-event-ctrl; + ctrl + Event data for event V4L2_EVENT_CTRL. + + __u8 @@ -109,9 +116,17 @@ 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[9] + reserved[8] Reserved for future extensions. Drivers must set the array to zero. diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml index 8b501791aa68..975f603a42ee 100644 --- a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml +++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml @@ -64,7 +64,19 @@ __u32 - reserved[7] + 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 . + + + __u32 + reserved[5] Reserved for future extensions. Drivers and applications must set the array to zero. @@ -99,6 +111,23 @@ 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 &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. + + V4L2_EVENT_PRIVATE_START 0x08000000 @@ -108,6 +137,23 @@ + + Event Flags + + &cs-def; + + + 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. Other events will ignore + this flag. + + + +
+ struct <structname>v4l2_event_vsync</structname> @@ -122,6 +168,100 @@
+ + 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;. + + + +
+ + + Changes + + &cs-def; + + + V4L2_EVENT_CTRL_CH_VALUE + 0x0001 + This control event was triggered because the value of the control + changed. Special case: if a button control is pressed, then this + event is sent as well, even though there is not explicit value + associated with a button control. + + + V4L2_EVENT_CTRL_CH_FLAGS + 0x0002 + This control event was triggered because the control flags + changed. + + + +
+