It's year 2022. Is Wayland ready for use?

TL;DR:

For KDE Plasma & Hi-DPI users, no.

Why Wayland?

The day before yesterday, I redecorated my workstation and borrowed an idle 1920×1080, 21.5' monitor. My laptop screen is 2880×1800, 14', and I wanted to set up dual-screen collaboration copying code is really convenient XD.

If each screen is set to its optimal scaling rate, the monitor should be at 100% scaling, while the laptop screen should be at 200% scaling. The problem is that X11-based desktop environments struggle to configure scaling rates per display (I heard from c10s that this is because the drawing part in X.org’s implementation is a single large buffer, not sure if it’s true >_<). You can only set a global scaling rate—either 100%, making the text on the laptop screen too small to read, or 200%, causing the monitor to overflow.

Wayland, on the other hand, was designed with multi-monitor support in mind, allowing each display to have its own resolution. Plus, it’s a more modern, future-oriented display protocol, so switching to Wayland is also part of the historical process.

How to Wayland?

For Manjaro + KDE users, installing the Wayland desktop environment is relatively simple:

sudo pacman -Sy --needed plasma-wayland-session xorg-xwayland libxcb egl-wayland

After logging out of the current session, you can select the Wayland session and log in.

Why NOT Wayland?

In the Wayland session, I encountered two major issues, and either one makes the system unbearable:

• xorg-xwayland allows running X windows, but it does not yet support high DPI, so these windows become very blurry at 200% scaling.

  • Firefox is broken
  • VS Code is broken
  • After these two broke, I didn’t want to test further

• The touchpad only supports scrolling, not clicking.

Since I wanted to focus on solving the first issue, I temporarily bypassed the second one by plugging in a mouse. I then found a package called xorg-xwayland-hidpi-git in the aur and archlinuxcn repositories. Judging by the name, this seemed to be what we were looking for.

Then I checked the AUR comments section—

@modnoob This adds an Xorg extension that needs to be supported by the compositor. The only implementation is in wlroots-hidpi-git, so only wlroot-based compositors can use it. AFAIK the only compositor using these patches on wlroots is sway-hidpi-git. No chance that Plasma (it's KDE, right?) can use these patches.

Ah, it’s broken.

So I didn’t even bother trying to solve the touchpad issue and quickly rolled back to the X.org happy place.

So...... When Wayland, exactly?

Actually, KDE mentioned the possibility of multi-monitor support and Wayland fully replacing X11 in their roadmap released in January this year... Well, it’s just a possibility.

In fact, this issue has been hanging around here for a long time, but it’s marked as "blocked due to waiting for upstream." So, until xorg-xwayland-hidpi-git is merged into the mainline xorg-xwayland, we probably won’t see any progress. Based on this, I’m very skeptical about using it this year...

What about the workstation issue?

The current workaround is to set the global scaling to 100%, place CLion and the browser (with normal font size) on the monitor, and place VS Code and the terminal (with enlarged fonts) on the laptop screen. If the boss sees this, maybe they’ll get me a Hi-DPI monitor.

An Unexpected Solution

Later, I discovered that X can provide display-level "scaling" using the xrandr command.

First, adjust the global scaling rate to 200% to ensure the laptop display is normal and sharp. Then, use xrandr --output <interface> --scale <scale> to adjust the scaling for a specific output. For example, I set it to 1.75x1.75, so X thinks the monitor’s resolution is 1.75 times 1920×1080—i.e., 3360×1890—and then downscales the output to 1920×1080 for display.

The downside is that the downscaled result is a bit blurry, but it’s the only way I know of to make both displays work at normal DPI under X. Still, 4K is the way to go.