Decided to uninstall my display manager and use startx instead. But now when I resume from suspend, the brightness keys cease to work until I log out and back in. Backlight does still respond when echoing into /sys/class/backlight/intel_backlight/brightness. But what kind of magic does a display manager do to keep brightness controls working after suspend and resume?

Using xfce on tty1 on an X230 if it matters.