I installed Ubuntu 16.04 recently, and had a problem with the Fn+F5 and Fn+F6 keys on my Asus K401UQ not changing the screen brightness. I tried the methods that were posted on different forums, about editing the grub configuration file.
Original Configuration -
quiet splash- The keys don't respond, but brightness can be adjusted through software(and settings).
acpi_osi=at the end,now the brightness keys respond and the onscreen brightness bar appears and changes, but no actual change in brightness. Software based control is lost.
acpi_osi=vendoretc, nothing works.
I have Intel HD Graphics 520 and Nvidia 940MX, currently using Nvidia driver software to toggle between both cards(No change even on nvidia card). Also tried default Xorg noveau driver. All the solutions Ive read over the past month don't seem to work. Thanks!