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-rw-r--r--Documentation/video4linux/v4l2-framework.txt18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 1feecfc..eb84795 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -350,6 +350,24 @@ VIDIOC_TRY_EXT_CTRLS
controls can be also be accessed through one (or several) V4L2 device
nodes.
+VIDIOC_DQEVENT
+VIDIOC_SUBSCRIBE_EVENT
+VIDIOC_UNSUBSCRIBE_EVENT
+
+ The events ioctls are identical to the ones defined in V4L2. They
+ behave identically, with the only exception that they deal only with
+ events generated by the sub-device. Depending on the driver, those
+ events can also be reported by one (or several) V4L2 device nodes.
+
+ Sub-device drivers that want to use events need to set the
+ V4L2_SUBDEV_USES_EVENTS v4l2_subdev::flags and initialize
+ v4l2_subdev::nevents to events queue depth before registering the
+ sub-device. After registration events can be queued as usual on the
+ v4l2_subdev::devnode device node.
+
+ To properly support events, the poll() file operation is also
+ implemented.
+
I2C sub-device drivers
----------------------
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