From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- .../DocBook/media/v4l/vidioc-subscribe-event.xml | 129 +++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 kernel/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml (limited to 'kernel/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml') diff --git a/kernel/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/kernel/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml new file mode 100644 index 000000000..d0332f610 --- /dev/null +++ b/kernel/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml @@ -0,0 +1,129 @@ + + + ioctl VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT + &manvol; + + + + VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT + Subscribe or unsubscribe event + + + + + + int ioctl + int fd + int request + struct v4l2_event_subscription +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_SUBSCRIBE_EVENT, VIDIOC_UNSUBSCRIBE_EVENT + + + + argp + + + + + + + + + Description + + Subscribe or unsubscribe V4L2 event. Subscribed events are + dequeued by using the &VIDIOC-DQEVENT; ioctl. + + + struct <structname>v4l2_event_subscription</structname> + + &cs-str; + + + __u32 + type + Type of the event, see . Note that +V4L2_EVENT_ALL can be used with VIDIOC_UNSUBSCRIBE_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 . + + + __u32 + reserved[5] + Reserved for future extensions. Drivers and applications + must set the array to zero. + + + +
+ + + 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 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 + &VIDIOC-S-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 &VIDIOC-S-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; + + -- cgit 1.2.3-korg