I updated to 18.04 and now my brightness keys are not working, even the brightness control bar isn't there. Sound control keys are working.
I checked for the graphics and there was this
llvmpipe (LLVM 8.0, 256 bits)
showing as graphics. I think this is why my brightness controls are turned off.
Any solution for this problem? Please answer for a newbie. I checked a few solutions but they were out of my understanding.