From: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
Add a new V4L2_EVENT_XFER_ERROR event to signal if an 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: adapted information what to do if this new event is received]
Signed-off-by: Michael Rodin <mrodin@xxxxxxxxxxxxxx>
---
.../userspace-api/media/v4l/vidioc-dqevent.rst | 10 ++++++++++
.../userspace-api/media/videodev2.h.rst.exceptions | 1 +
include/uapi/linux/videodev2.h | 1 +
3 files changed, 12 insertions(+)
diff --git a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
index 6eb40073c906..3cf0b4859784 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-dqevent.rst
@@ -182,6 +182,16 @@ 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 an error is detected on a video bus in
+ the pipeline. If a driver receives this event from an upstream
+ subdevice, it has to forward the event to userspace. The streaming
+ application has to check if the transfer error is unrecoverable,
+ i.e. no new buffers can be dequeued from the kernel after the
+ expected time. If the error is unrecoverable, the streaming
+ application should 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 9cbb7a0c354a..25bde61a1519 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 5311ac4fde35..44db724d4541 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2385,6 +2385,7 @@ 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 */
--
2.25.1
