A Moonlight client connecting to the x11-backend host got a black screen
even though pairing, NVENC, and input injection all worked: the headless
Xorg on :0 had no window manager rendering on it, so capture=x11 grabbed
an empty black root window. (The wlr/kms backends don't hit this — their
capture source renders for itself.)
This was a hand-built path with nothing in the repo to reproduce the
desktop piece. Now:
- files/headless-desktop.service: Openbox session on :0, bound to
xorg-headless.service, enabled via default.target for lingering boots,
with a best-effort xsetroot so the desktop is visibly non-black.
- lib/headless.sh: capture_backend_is_x11 + install_headless_desktop
(idempotent; pulls openbox/xsetroot via the distro dispatch).
- install.sh: installs the desktop unit when capture=x11 is detected.
- status.sh: x11 branch now FAILs if no window manager is on :0 instead
of only checking the X server answers — the gap that hid this failure.
- docs: TROUBLESHOOTING §13 black-screen lesson; FOLLOWUPS P3 updated.
Part of the P3 x11-backend work; --backend flag, config.sh x11 variant,
and xorg-headless templates remain outstanding.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Woodard
6fc34a2bd2