ret = ops->vidioc_querycap(file, fh, cap);
cap->capabilities |= V4L2_CAP_EXT_PIX_FORMAT;
+ /*
+ * Drivers MUST fill in device_caps, so check for this and
+ * warn if it was forgotten.
+ */
+ WARN_ON(!(cap->capabilities & V4L2_CAP_DEVICE_CAPS) ||
+ !cap->device_caps);
cap->device_caps |= V4L2_CAP_EXT_PIX_FORMAT;
return ret;