From: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
Add a new V4L2_EVENT_XFER_ERROR event to signal if a unrecoverable error
happens during video transfer.
The use-case that sparked this new event is to signal to the video
device driver that an error has happen on the CSI-2 bus from the CSI-2
receiver subdevice.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
[mrodin@xxxxxxxxxxxxxx: added information what to do if this new event is received]
Signed-off-by: Michael Rodin <mrodin@xxxxxxxxxxxxxx>
---
Documentation/userspace-api/media/v4l/vidioc-dqevent.rst | 9 +++++++++
Documentation/userspace-api/media/videodev2.h.rst.exceptions | 1 +
include/uapi/linux/videodev2.h | 1 +
3 files changed, 11 insertions(+)
diff --git a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
index 6eb4007..ed0a5ff 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
@@ -182,6 +182,15 @@ call.
the regions changes. This event has a struct
:c:type:`v4l2_event_motion_det`
associated with it.
+ * - ``V4L2_EVENT_XFER_ERROR``
+ - 7
+ - This event is triggered when an transfer error is detected while
+ streaming. For example if a unrecoverable error is detected on a video
+ bus in the pipeline. If a driver receives this event from an upstream
+ subdevice, it has to check if it is affected by this error and then try
+ to recover from this error. If an internal recovery is not possible,
+ then it can forward the event to userspace so the streaming application
+ has to restart streaming if it wants to continue.
* - ``V4L2_EVENT_PRIVATE_START``
- 0x08000000
- Base event number for driver-private events.
diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
index 9cbb7a0..25bde61 100644
--- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
+++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
@@ -500,6 +500,7 @@ replace define V4L2_EVENT_CTRL event-type
replace define V4L2_EVENT_FRAME_SYNC event-type
replace define V4L2_EVENT_SOURCE_CHANGE event-type
replace define V4L2_EVENT_MOTION_DET event-type
+replace define V4L2_EVENT_XFER_ERROR event-type
replace define V4L2_EVENT_PRIVATE_START event-type
replace define V4L2_EVENT_CTRL_CH_VALUE ctrl-changes-flags
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 6d465dc..8c75bd8 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2383,6 +2383,7 @@ struct v4l2_streamparm {
#define V4L2_EVENT_FRAME_SYNC 4
#define V4L2_EVENT_SOURCE_CHANGE 5
#define V4L2_EVENT_MOTION_DET 6
+#define V4L2_EVENT_XFER_ERROR 7
#define V4L2_EVENT_PRIVATE_START 0x08000000
/* Payload for V4L2_EVENT_VSYNC */
--
2.7.4
