pastilhasandClaude Opus 5
83bf746ab8
The TV runs at 4K so it can play 4K video; a usable remote desktop wants about 1080p. One framebuffer
cannot be both, so mirroring meant every remote session was a scaled-down 4K desktop — dense to read
and expensive to encode. This gives remote its own display at 1920x1080 and leaves the TV alone.
Xvnc (TigerVNC) rather than x11vnc: it is the X server AND the VNC server in one process, so nothing
polls or scales — the server knows which rectangles changed and encodes them directly, where x11vnc
had to diff a framebuffer it did not own. It also implements RandR SetDesktopSize, so the client's
existing resizeSession makes the desktop resize itself to the browser panel. No scaling on either
side at any panel size, which removes the density problem rather than trading it for blur.
XFCE rather than GNOME, and NOT because it is lighter. Ubuntu's GNOME is managed by per-USER systemd
units — org.gnome.Shell@x11.service, gnome-session-manager@ubuntu.service and the whole
org.gnome.SettingsDaemon.* set all sit under user@<uid>.service, and gnome-session@.target is marked
RefuseManualStart. A second GNOME session for the SAME user collides with every one of them. That is
almost certainly what 106e5bd recorded as "a ghost logind session that broke lightdm login" — a
property of the session model, not something care avoids. XFCE has no such per-user units and
coexists with the TV session: same user, same home, same files, different shell.
The cookie goes in ~/.vnc/Xauthority, not ~/.Xauthority, which belongs to the TV session and is not
ours to write. Display is chosen by scanning for a free number from :2 up, checking the lock file as
well as the socket because a stale lock alone stops an X server starting. Teardown kills the session
before the server, since killing Xvnc first leaves XFCE's children reparented and running.
Verified end to end on a scratch display before committing: Xvnc listened, XFCE came up with xfwm4,
xfdesktop, xfce4-panel and xfsettingsd, RandR reported a 1920x1080 VNC-0 output, and the GNOME
session on the TV was untouched throughout.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>