Here's a somewhat interesting account from what seems to me like a duplicate. I think I can confirm what he says about values in /proc/acpi/video/VID/LCD0/brightness
Bug #613638 Adjusting brightness broken after hibernate/suspend -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/562005 Title: Backlight controls of laptops with NVIDIA NVS and Quadro FX 880M GPUs no longer function while using proprietary drivers -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
