[0/4] media: videobuf2: Add a transfer error event

Message

Niklas Söderlund Nov. 8, 2021, 4:02 p.m. UTC

Hello,

This series adds a new V4L2 event, V4L2_EVENT_XFER_ERROR. This new event 
is intended to be used when a device in the capturing pipeline 
encounters an unrecoverable error and needs to inform the capturing 
application thru the video node about the error.

The fist use-case for this is also demonstrated in this series by the 
R-Car CSI-2 receiver that generates the new event when it detects an 
error on the bus.

Patch 1/4 is a bug fix for the R-Car VIN driver that was found while 
working on this series. This patch is good to be picked-up on it's own 
but is a requirement for later patches in this series so I have opted to 
include it here as the first patch. 

Patch 2/4 adds the new V4L2 event. While patch 3/4 and 4/4 makes use of 
it in the R-Car capture pipeline. Careful readers will note that the 
last to patches already have a patch history. This is because they have 
been part of an earlier attempt a while back to solve this issue in a 
different way, and during those discussions the need for this new event 
was found.

Niklas Söderlund (4):
  media: rcar-vin: Free buffers with error if hardware stop fails
  media: videobuf2: Add a transfer error event
  rcar-vin: Stop stream when subdevice signal transfer error
  rcar-csi2: Do not try to recover after transfer error

 .../userspace-api/media/v4l/vidioc-dqevent.rst  |  5 +++++
 .../media/videodev2.h.rst.exceptions            |  1 +
 drivers/media/platform/rcar-vin/rcar-csi2.c     | 17 +++++++++--------
 drivers/media/platform/rcar-vin/rcar-dma.c      | 10 ++++++++++
 drivers/media/platform/rcar-vin/rcar-v4l2.c     | 17 ++++++++++++++++-
 include/uapi/linux/videodev2.h                  |  1 +
 6 files changed, 42 insertions(+), 9 deletions(-)