AltGr not working with UHID keyboard + Danish keyboard layout

Utilizing the UHID keyboard with scrcpy and the Danish keyboard layout does so that AltGr cannot be utilized.

System Specs

• Operating system: Arch Linux
• Display server protocol: Wayland
• Compositor: Sway
• Keyboard Layout: Utilizing the danish keyboard layout as can be seen here:

(source of picture here)

Phone specs

• Phone: Google pixel 9 pro XL
• Operating system: GrapheneOS.
• Keyboard: Using the default android keyboard bundled with GrapheneOS, Danish layout.

Description of problem

Scrcpy is running through xwayland.

Running scrcpy --video-codec=h265 --max-size=1920 --max-fps=60 --no-audio --keyboard=uhid --shortcut-mod lalt -V verbose and pressing+releasing AltGr gives the following output:

VERBOSE: hid keyboard: key down scancode=e6 (230) mod=00 VERBOSE: input: UHID input [1] 00 00 00 00 00 00 00 00 VERBOSE: hid keyboard: key up scancode=e6 (230) mod=00 VERBOSE: input: UHID input [1] 00 00 00 00 00 00 00 00

However, upon pressing e.g. AltGr+2 to input the character '@' in scrcpy, the character is not input. '2' is simply input.

There is an odd thing, however. The ´-button (located just to the left of the backspace button on my keyboard) does not input anything in scrcpy when pressed on its own. However, if the ´-button is pressed twice with AltGr held down in scrcpy, the character ´ is input.

This character is normally input when pressing the button on its own without AltGr in my operating system.

The following output is obtained by Pressing AltGr-->pressing the ´-button twice -->releasing AltGr in scrcpy:

VERBOSE: hid keyboard: key down scancode=e6 (230) mod=00 VERBOSE: input: UHID input [1] 00 00 00 00 00 00 00 00 VERBOSE: keys[2e] = true VERBOSE: hid keyboard: key down scancode=2e (46) mod=00 VERBOSE: input: UHID input [1] 00 00 2E 00 00 00 00 00 VERBOSE: keys[2e] = false VERBOSE: hid keyboard: key up scancode=2e (46) mod=00 VERBOSE: input: UHID input [1] 00 00 00 00 00 00 00 00 VERBOSE: keys[2e] = true VERBOSE: hid keyboard: key down scancode=2e (46) mod=00 VERBOSE: input: UHID input [1] 00 00 2E 00 00 00 00 00 VERBOSE: keys[2e] = false VERBOSE: hid keyboard: key up scancode=2e (46) mod=00 VERBOSE: input: UHID input [1] 00 00 00 00 00 00 00 00 VERBOSE: hid keyboard: key up scancode=e6 (230) mod=00 VERBOSE: input: UHID input [1] 00 00 00 00 00 00 00 00

AltGr works completely fine in scrcpy with the --keyboard=sdk option, however.

A recent-ish comment in this issue #4725 describes a similar problem to mine.