KERNEL=="video*", ENV{ID_SERIAL}=="?*", SYMLINK+="v4l/by-id/$env{ID_BUS}-$env{ID_SERIAL}-video-index$attr{index}"
# check for valid "index" number
TEST!="index", GOTO="persistent_v4l_end"
ATTR{index}!="?*", GOTO="persistent_v4l_end"
KERNEL=="video*", ENV{ID_SERIAL}=="?*", SYMLINK+="v4l/by-id/$env{ID_BUS}-$env{ID_SERIAL}-video-index$attr{index}"
# check for valid "index" number
TEST!="index", GOTO="persistent_v4l_end"
ATTR{index}!="?*", GOTO="persistent_v4l_end"