Always could not load rendering backend linuxkms-*

[Quackdoc]

Bug Description

When trying to run any of the linuxkms backends I get the following issue Could not load rendering backend linuxkms-skia, fallback to default

This issue occurs with the slint-rust-template as well as slint-viewer

Reproducible Code (if applicable)

Environment Details

• Slint Version: #504474f90b39bdbf43043a6e31859f24572c59a0
• Platform/OS: Arch Linux
• Programming Language: Rust
• Backend/Renderer: all linuxkms

Product Impact

No response

[tronical]

The linuxkms backed is not enabled by default. Try adding "backend-linuxkms" into your features:

https://docs.slint.dev/latest/docs/rust/slint/docs/cargo_features/#backends

slint = { version = "1.12", features = ["backend-linuxkms", "renderer-skia"] }

[Quackdoc]

I thought slint-viewer did have it enabled? Would it be viable to enable it there by default? I would like to ship slint-viewer as a package.

[ogoffart]

How are you building or getting the slint-viewer?
The one we build in out CI and is in our binary package should have the feature enabled.
Otherwise you can pass --features=backend-linuxkms when building

(Our binary are using the -noseat variant. Maybe that is a problem)

[Quackdoc]

I had just used cargo install --git .... I did try using sudo to execute, but that didnt work, maybe I needed to use su.

I did explicitly add --features=backend-linuxkms and got i-slint-backend-linuxkms v1.12.1 (/home/quack/.cargo/git/checkouts/slint-774a37e469fae6bf/596775a/internal/backends/linuxkms) is being compiled in.

now when I run slint-viewer --auto-reload --backend linuxkms-software main.slint I get

cat /tmp/slint.log
warning: ':=' to declare a component is deprecated. The new syntax declare components with 'component MyComponent {'. Read the documentation for more info
 --> main.slint:5:3
  |
5 | _ := Dialog {
  |   ^
warning: Component is implicitly marked for export. This is deprecated and it should be explicitly exported
 --> main.slint:5:1
  |
5 | _ := Dialog {
  | ^

qt.qpa.xcb: could not connect to display
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vkkhrdisplay, vnc, xcb, wayland-egl, wayland.

same thing if I use linuxkms-femtovg