If you're having this problem on an Acer/eMachines/Packard Bell/Gateway laptop, try booting with i915.invert_brightness=1 module parameter (https://help.ubuntu.com/community/BootOptions). If it works, consider filing an upstream bug on Product=DRI, Component=DRM/Intel (https://01.org/linuxgraphics/documentation/how-report-bugs-0) with the output of 'lspci -vmmnn' attached.
If you're having this problem on an Acer/eMachines/ Packard Bell/Gateway laptop, try booting with i915.invert_ brightness= 1 module parameter (https:/ /help.ubuntu. com/community/ BootOptions). If it works, consider filing an upstream bug on Product=DRI, Component=DRM/Intel (https:/ /01.org/ linuxgraphics/ documentation/ how-report- bugs-0) with the output of 'lspci -vmmnn' attached.