Another E330:
OS: Ubuntu 14.04 64bit
Manufacturer: Lenovo
Model: Thinkpad Edge E330
Specification: i5-3210M, 4GB DDR3, 500GB HDD, GbE NIC, WiFi, Bluetooth, IGP, Camera, 13.3".

For a working backlight control, it needs:
GRUB_CMDLINE_LINUX_DEFAULT="thinkpad-acpi.brightness_enable=1 acpi.brightness_switch_enabled=0 quiet splash"