Hello, I believe you are the creator of v4l2-compliance, right? My hope is that you might be able to lead me in the right direction. I am currently finishing up a sensor driver that I ported from a downstream kernel. And I try to clear up the last compliance error: ``` info: checking control event 'User Controls' (0x00980001) VIDIOC_SUBSCRIBE_EVENT returned -1 (Inappropriate ioctl for device) fail: v4l2-test-controls.cpp(818): subscribe event for control 'User Controls' failed test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: FAIL ``` I notice that it calls a normal v4l2 ioctl on my subdevice. I implemented the event handling just like I was able to find in other devices like: imx219, imx355, ov2640 by adding: ``` #include <media/v4l2-event.h> ... sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS; ... static const struct v4l2_subdev_core_ops ov13850_core_ops = { ... .subscribe_event = v4l2_ctrl_subdev_subscribe_event, .unsubscribe_event = v4l2_event_subdev_unsubscribe ... ``` Am I supposed to correct that error, or asked in another way is it actually an error when a subdevice doesn't implement VIDIOC_SUBSCRIBE_EVENT? Additionally, I noticed that the compliance check doesn't look at my VIDIOC_SUBDEV_G_SELECTION implementation but instead searches for any implementation of the VIDIOC_G_SELECTION ioctl. I invoked the compliance test with: v4l2-compliance -u /dev/v4l-subdev3 -v -T My current code can be located here: https://github.com/initBasti/Linux_kernel_media_tree_fork/blob/fix_subscribe_event_user_controls/drivers/media/i2c/ov13850.c Greetings and thanks in advance, Sebastian