TethrLink

TethrLink turns an Android tablet into a real second monitor for your Linux PC — not a mirror of a screen you already have — over a direct USB connection. No Wi-Fi, no router, no cloud, no account.

The PC asks GNOME to create a dedicated virtual display, captures it through PipeWire, encodes it with H.264, and streams it down the cable. The tablet appears in Settings → Displays like any other monitor: put it above, below or beside your laptop, and windows you drag onto it stay there.

The display size is worked out from both ends of the connection — its height from your monitor, its aspect ratio from the tablet — so the shared edge is fully crossable for the pointer and nothing is stretched on the panel. A 1920×1080 laptop with a 2960×1848 tablet gives 1730×1080.

Features:
• A real second display, not a screen mirror
• Zero-config transport — USB tethering, no router needed
• Auto-discovery — the app finds the server itself, no IP to type
• Display size derived from your monitor and the tablet's panel
• GTK4 and Libadwaita desktop app
• Serves only devices on a USB-attached interface; Wi-Fi and container bridges are refused

Requirements:
• GNOME on Wayland. The virtual display uses Mutter's ScreenCast API, which has no cross-compositor equivalent. X11 sessions fall back to JPEG at your own screen's resolution.
• An Android tablet running 5.0 or later, with USB tethering, and the TethrLink app installed.

Known limitations of this package:
• Software encoding only. Hardware H.264 needs VA-API drivers that aren't available inside the snap; the .deb and from-source installs use your GPU normally.
• Touch input, added in 2.0.0, is not available in the snap yet — it needs desktop permissions this package cannot currently request. Use the .deb if you want the tablet to drive your pointer.
• One tablet at a time.
• An idle session costs roughly half a core, because holding a steady frame rate means running the pipeline even when the screen isn't changing.

Get the Android app and the .deb from the GitHub releases page.

Source, issues and documentation: https://github.com/princesavsaviya/TethrLink