No brightness control in Windows 10 on XPS 14 (L421X, Mid 2012). Had this same problem in Windows 8/8.1. Before, using Dell's outdated driver in lieu of a more recent one from Intel brought back the brightness control functionality.

Dell has released their drivers (already outdated) for this laptop for Windows 10, and it is listed as being supported for Windows 10. Is there any chance we can get some working drivers?