The Steam controller is running fine in Steam app's big picture mode, but when I load a game and try to use the controller, there's no response to in-game activity. I can use it, however, to open and navigate through the Steam menu by pressing the Steam button. (I already tried this solution, to no avail: How do I get a Steam Controller working?)
How can I get the controller to work in games?
Running: Ubuntu GNOME 17.04 x64 GNOME 3.24.1 Linux kernel 4.10.0-21-generic Steam beta client (built May 26, 2017)