Ubuntu Touch Convergence

The Feature That Justifies the Whole Setup

In the previous post I made the case for Ubuntu Touch on a
Fairphone 4 as a daily driver with honest limits. The backups are
manual, some banking apps do not run, VoLTE is a gamble. What I
deferred to this post is the feature that sits on the other side
of the ledger and, for the right kind of user, outweighs all of
it: convergence.

Convergence is the property that the same operating system, on the
same device, presents a phone interface on the phone screen and a
desktop interface on an external monitor. Not a cast. Not a mirror.
Not a remote session. The actual desktop, driven by the actual
phone, using the same applications that adapt their layout to the
screen they are shown on. Plug the Fairphone 4 into a monitor over
USB-C, pair a keyboard, and the phone in your hand becomes a small
Linux workstation.

This post is the practical writeup of getting that working: the
monitor over USB-C, the Bluetooth keyboard, and the detail that
surprises everyone the first time, which is that the phone's own
touchscreen becomes the trackpad for the desktop session.

The Monitor Over USB-C

The Fairphone 4 supports Display Out over its USB-C port. This is
not universal on phones, and it is one of the specific reasons the
Fairphone 4 is a good Ubuntu Touch device rather than merely a
possible one. The USB-C port carries a DisplayPort Alternate Mode
signal, which means a single cable from the phone to a monitor
carries video directly, with no adapter chip doing lossy
conversion in the middle.

The physical setup is a USB-C to HDMI or USB-C to DisplayPort
cable, or a USB-C hub if you want power delivery and peripherals
on the same connection. When the monitor is connected, Ubuntu
Touch detects the external display and switches it into desktop
mode automatically. The monitor shows a windowed desktop
environment, based on the same Lomiri shell that drives the phone
interface, but laid out for a large screen with a taskbar,
windowed applications, and the desktop conventions you expect.

The applications that appear are the same ones installed on the
phone. The Morph browser, the terminal, the file manager, the
note-taking app: each adapts from its phone layout to a desktop
window. This is the payoff of the convergent application model.
The developer wrote one application, and it presents correctly on
both form factors. An application that is a cramped single column
on the phone becomes a proper multi-pane desktop window on the
monitor.

For power delivery, a USB-C hub with a PD input keeps the phone
charging while it drives the display, which matters because
driving an external monitor is one of the more power-hungry things
the phone can do. Without power delivery, an extended desktop
session will drain the battery faster than casual phone use. With
it, the phone runs indefinitely as a desktop.

The Bluetooth Keyboard

A desktop without a keyboard is a display, not a workstation. The
keyboard pairs over Bluetooth through the standard Ubuntu Touch
Bluetooth settings. Open the Bluetooth settings, put the keyboard
into pairing mode, select it from the discovered devices, confirm
the pairing.

Bluetooth on Ubuntu Touch is, as I noted in the previous post,
occasionally temperamental. Keyboards are among the better-behaved
Bluetooth devices, though, because the HID profile they use is
simple and well-supported. My experience with a standard Bluetooth
keyboard has been reliable. The pairing survives reboots. The
keyboard reconnects automatically when it comes into range and is
powered on. The latency is imperceptible for typing.

Once the keyboard is paired, it drives the desktop session on the
monitor exactly as a keyboard drives any Linux desktop. Keyboard
shortcuts work. The terminal accepts input at full speed. Text
editing in the browser and the native apps behaves as expected.
The combination of the external monitor and the physical keyboard
is the point at which the setup stops feeling like a phone
pretending to be a computer and starts feeling like a computer
that happens to be phone-sized.

A USB keyboard through the same hub works identically and avoids
the Bluetooth variability entirely. If reliability matters more
than cable-free tidiness, a wired keyboard through the hub is the
more predictable choice. I use Bluetooth because the tidiness is
worth the occasional reconnection, but the wired path is there for
anyone who prefers it.

The Phone as the Pointer

Here is the detail that surprises everyone the first time they see
it. With the monitor showing the desktop and the keyboard handling
text, the obvious missing piece is the mouse. You can pair a
Bluetooth mouse, and it works. But you do not have to, because the
phone's own touchscreen becomes the trackpad.

When Ubuntu Touch is in desktop mode driving an external monitor,
the phone screen switches into a pointer surface. Sliding a finger
across the phone's touchscreen moves the cursor on the monitor,
exactly like a laptop trackpad. Tapping the phone screen is a
click. The gestures map the way a trackpad's do. The phone, held
in one hand or resting on the desk beside the keyboard, becomes
the pointing device for the desktop it is driving.

This is genuinely clever, and it solves the practical problem that
you do not want to carry a mouse to use a phone as a desktop. The
whole appeal of convergence is that the computer is the phone you
already have in your pocket. Requiring a separate mouse would
undercut that. Making the phone's own screen the trackpad closes
the loop: phone plus one cable plus one keyboard equals a complete
workstation, with the pointing device being the phone itself.

The ergonomics take a few minutes to settle into. A phone
touchscreen as a trackpad is smaller than a laptop trackpad and
sits flat on the desk rather than angled under your palm. For
precision work it is adequate rather than excellent. For the
navigation that a browser-and-terminal workflow actually involves,
clicking links, positioning a cursor, switching windows, it is
completely sufficient. And it is always there, requiring nothing
you did not already bring.

What the Complete Setup Looks Like

Assembled, the workstation is: the Fairphone 4, one USB-C cable to
a hub, the hub connected to a monitor and to power, a Bluetooth
keyboard paired, and the phone lying on the desk as the trackpad.
Total additional hardware beyond the phone: a cable, a hub, a
keyboard, and a monitor you probably already own. Total weight
added to what you carry: a cable, a small hub, and a keyboard if
you want one that travels.

The session that results is a real Linux desktop. The terminal is
a real terminal, which for my work is most of what I need: SSH
into the homelab, run the commands, read the output on a large
screen with a real keyboard. The browser is a real browser, which
covers most of the rest. For a workflow that is largely SSH
sessions and web interfaces, this is a complete computing
environment carried in a pocket and assembled from a monitor at
whatever desk you happen to be at.

The limits from the previous post still apply. The applications
are the convergent ones, not the entire Linux desktop catalog. You
are not running arbitrary apt packages in this desktop; you are
running the Ubuntu Touch applications in their desktop layout, plus
whatever runs in the terminal, plus Waydroid's Android apps if you
start the container. For the person whose desktop needs are a
terminal, a browser, and a handful of native tools, this is
enough. For the person who needs a full desktop application suite,
it is not, and a laptop remains the right tool.

Why This Matters Beyond the Novelty

It would be easy to file convergence under "clever trick" and move
on. That undersells it. The reason convergence matters is that it
collapses the distinction between the phone and the computer for a
specific and increasingly common kind of user.

If your actual computing is SSH, a browser, and some text, then
the hardware that computing requires is a screen and a keyboard,
both of which are commodity items available at any desk. The
expensive, personal, data-carrying part is the compute and the
storage and the identity, and all of that fits in the phone. The
convergent phone means you carry the part that matters and borrow
the parts that do not. Arrive at a desk, plug into whatever monitor
is there, pair a keyboard, and your actual working environment is
present, driven by the device that was in your pocket, with your
data and your sessions and your configuration exactly as you left
them.

That is a genuinely different relationship with computing hardware
than the mainstream model, where the phone and the laptop are
separate devices with separate data and separate maintenance. The
convergent model treats the phone as the computer and everything
else as a peripheral. For the right workflow, that is not a
novelty. It is a better architecture.

Closing

Convergence on the Fairphone 4 is the feature that turns the
honest-limits daily driver of the previous post into something the
mainstream phones cannot match at any price. Plug in over USB-C
for the monitor, pair a Bluetooth keyboard, use the phone's own
touchscreen as the trackpad, and the phone becomes a Linux
workstation assembled from whatever screen is in front of you.

The setup takes a few minutes. The hardware is a cable, a hub, and
a keyboard. The result is a desktop driven by the phone in your
pocket, using your data, your sessions, and your configuration,
with the pointing device being the phone itself. For a
terminal-and-browser workflow, it is a complete computing
environment that weighs nothing beyond what you already carry.

The mainstream phones have more apps, better cameras, and
effortless backups. They do not have this. For the user whose
computing fits through a terminal and a browser, this one feature
is worth more than all the things Ubuntu Touch gives up to provide
it.