Could you give the output of Code: devel-su mcetool | grep 'Adaptive dimming threshold' It should be 10000msecs If not you can adjust it with Code: devel-su mcetool --set-adaptive-dimming-time=10000 or whichever value you want. If you haven't installed mce-tools already install them with Code: pkcon install mce-tools
devel-su mcetool | grep 'Adaptive dimming threshold'
devel-su mcetool --set-adaptive-dimming-time=10000
pkcon install mce-tools