Bisected to this commit: https://cgit.freed= esktop.org/~agd5f/linux/commit/?h=3Damd-staging-4.9&id=3Dafbeb2d0961b21= 39bcf6553a710e6a8ae5d09d34 Which makes me think I'm experiencing a different issue, because this bug w= as reported long before that commit emerged. My reproducer is to fill the screen with two xterm windows next to each oth= er and generate random lines of text in both of them, using command like this = for example: tr -dc a-z1-4 </dev/urandom | tr 1-2 ' \n' | awk 'length=3D=3D0 || lengt= h>50' | tr 3-4 ' ' | sed 's/^ *//' | cat -s | sed 's/ / /g' | fmt The screen lock will occur in a couple of minutes.