[qt.qpa.xcb] QtWarning: could not connect to display

[andresimi]

Hi guys, after the last update on flathub I started to get this error when loading CopyQ.

andresimi@andredesk:~$ flatpak run com.github.hluk.copyq
Warning: [qt.qpa.xcb] QtWarning: could not connect to display 
Warning: [qt.qpa.plugin] QtWarning: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
ERROR: [default] QtFatal: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
ERROR:    
ERROR:    Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vkkhrdisplay, vnc, wayland-egl, wayland, xcb.
ERROR:    
terminate called after throwing an instance of '(anonymous namespace)::ExceptionQtFatal'
  what():  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, wayland-egl, wayland, xcb.


andresimi@andredesk:~$ flatpak info com.github.hluk.copyq

CopyQ - Advanced clipboard manager

        ID: com.github.hluk.copyq
       Ref: app/com.github.hluk.copyq/x86_64/stable
      Arq.: x86_64
      Ramo: stable
    Versão: 9.1.0
   Licença: GPL-3.0+
    Origem: flathub
   Coleção: org.flathub.Stable
Instalação: system
 Instalado: 9,2 MB
   Runtime: org.kde.Platform/x86_64/6.8
       Sdk: org.kde.Sdk/x86_64/6.8

    Commit: 9e9ead171aae94d302a2dcc41aeba487b24d27bbc2518b69d3c15f36c6b01c5f
       Pai: 638c7e0cd891bca0bed1fa570f1a662a7871ed8e76b120fa4471df3c6c1986e4
   Assunto: Avoid showing "Legacy windowing system" warning on flathub (#68) (b29c9477)
      Data: 2025-01-15 07:51:10 +0000

I am runing on Fedora 41 Silverblue.

Could you help?

[randogoth]

I have the same issue on Fedora 41 Silverblue (Bluefin)

[andresimi]

Yeah, there must be a problem with the last commit (9e9ead171aae94d302a2dcc41aeba487b24d27bbc2518b69d3c15f36c6b01c5f). When I go back to this one it works again.

CopyQ - Advanced clipboard manager

        ID: com.github.hluk.copyq
       Ref: app/com.github.hluk.copyq/x86_64/stable
      Arq.: x86_64
      Ramo: stable
    Versão: 9.1.0
   Licença: GPL-3.0+
    Origem: flathub
   Coleção: org.flathub.Stable
Instalação: system
 Instalado: 9,2 MB
   Runtime: org.kde.Platform/x86_64/6.8
       Sdk: org.kde.Sdk/x86_64/6.8

    Commit: 638c7e0cd891bca0bed1fa570f1a662a7871ed8e76b120fa4471df3c6c1986e4
       Pai: 1ba1e9a57b61ed2195cbef281bb3cd264a5f51eb8ae5d7ecc784a3c27ff2fad1
   Assunto: Update KDE runtime to 6.8, add x-checker-data, rearrange module `copyq` (#67) (728bce5c)
      Data: 2025-01-14 15:32:36 +0000

[randogoth]

I got it to work by disabling Wayland in Flatseal and adding the environment variable QT_QPA_PLATFORM=xcb

[hluk]

Looks like this is related to flathub/com.github.hluk.copyq#68.

It might be some flatpak issue, since the app should start the properly in X11 and Wayland.

I believe it should be still possible to start the app in Wayland in X11 mode (XWayland) with the following command:

env QT_QPA_PLATFORM=xcb flatpak run --socket=x11 com.github.hluk.copyq

[randogoth]

I believe it should be still possible to start the app in Wayland in X11 mode (XWayland) with the following command:

env QT_QPA_PLATFORM=xcb flatpak run --socket=x11 com.github.hluk.copyq

Unfortunately that is not the case. Same error. But the workaround I mentioned works.