An apt upgrade switched the display manager from SDDM to plasmalogin,
whose kwin_wayland greeter never runs the SDDM Xsetup hook. Add a
plasma-login.service user drop-in that cycles DPMS off/on with
kscreen-doctor on 7.x kernels, forcing the full modeset that un-sticks
i915 pipe A (a plain resolution change is absorbed by the eDP panel
fitter and doesn't help). Verified across a cold reboot.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>