backend/drm: ensure disconnected outputs are disabled after VT switch

The following situation can be dangerous:

- Output DP-1 is plugged in, compositor enables it.
- User VT switches away.
- User unplugs DP-1.
- User VT switches back.
- scan_drm_connectors() figures out the output is now disconnected,
  uninitializes the struct wlr_output.
- The loop restoring previous output state in handle_session_active()
  accesses the struct wlr_output to figure out what to restore.

By chance, we zero out the struct wlr_output after uninitializing it,
so enabled and current_mode will always be zero. But let's make sure
we handle this case explicitly, to remind future readers that it exists
and make the code less fragile.

0 files changed, 0 insertions, 0 deletions