VIDIOC_G_CTRL cannot always be translated to VIDIOC_G_EXT_CTRLS

[Gnurou]

Right now we are wrapping calls to G_CTRL into G_EXT_CTRLS in order to limit the number of ioctls we need to support.

This works most of the time, except when quering a 64-bit control: in this case G_CTRL is supposed to return -EINVAL because the value type of v4l2_ctrl is 32-bit and thus cannot hold the requested control's value (same for string and class controls). The following code in v4l2-compliance is what enforces this:

		if (qctrl.type == V4L2_CTRL_TYPE_INTEGER64 ||
		    qctrl.type == V4L2_CTRL_TYPE_STRING ||
		    qctrl.type == V4L2_CTRL_TYPE_CTRL_CLASS) {
			ret = doioctl(node, VIDIOC_G_CTRL, &ctrl);
			if (ret != EINVAL &&
			    !((qctrl.flags & V4L2_CTRL_FLAG_WRITE_ONLY) && ret == EACCES))

So it seems like we have to forward the G_CTRL and S_CTRL ioctls to the host in order to handle this case.