v4l2: populate video_buffer mem field at dequeue

Our v4l2_queue_buffer and v4l2_dequeue_buffer functions give us a
wrapper around the raw V4L2 ioctls with a wrapper struct video_buffer
around the raw struct v4l2_buffer. The problem is that the
video_buffer's mem field is never populated, so there's no way to access
the mem that the buffer refers to given only the buffer.

Populate the video_buffer's mem field at v4l2_dequeue_buffer based on
the dequeued v4l2 buf's index.

Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/v4l2.c b/lib/v4l2.c
index 6702ece..7bcbd73 100644
--- a/lib/v4l2.c
+++ b/lib/v4l2.c
@@ -789,6 +789,7 @@ int v4l2_dequeue_buffer(struct v4l2_device *dev, struct video_buffer *buffer)
 	}
 
 	buffer->index = buf.index;
+	buffer->mem = dev->buffers.buffers[buf.index].mem;
 	buffer->bytesused = buf.bytesused;
 	buffer->timestamp = buf.timestamp;
 	buffer->error = !!(buf.flags & V4L2_BUF_FLAG_ERROR);