Some flatpak apps do not work on X11, but do work on Wayland

[garrett]

Linux distribution and version

Fedora 33 beta, Silverblue

Flatpak version

Flatpak 1.8.2

RPM: flatpak-1.8.2-2.fc33.x86_64
Silverblue: 33.20200929.n.0 (2020-09-29T08:06:48Z), 215677333515cc11110cf016a4cbb021eb929b552f5ed25bb6d403c9f19c1a4a

Description of the problem

Launching some apps simply doesn't work from the UI when in X11. They work in Wayland.

Launching the same apps from the terminal show the following:

$ flatpak run org.mozilla.firefox

(firefox:2): Gtk-WARNING **: 10:17:33.993: cannot open display: 

$ flatpak run org.gnome.Characters
Unable to init server: Could not connect: Connection refused

(org.gnome.Characters:2): Gtk-WARNING **: 10:07:23.167: cannot open display: 

$ flatpak run org.gnome.Epiphany.Devel
Unable to init server: Could not connect: Connection refused
Failed to parse arguments: Cannot open display: 

Steps to reproduce

Use Fedora 33 (possibly Silverblue), try to use some apps from Flathub. Some will work, some will not. The ones that don't work consistently do not work, including Firefox and GNOME Characters.

These work:

• com.calibre_ebook.calibre
• org.darktable.Darktable
• org.signal.Signal
• org.gimp.GIMP
• org.inkscape.Inkscape
• org.gnome.Evolution
• org.gnome.Geary

These do not work:

• org.mozilla.firefox
• org.gnome.Characters
• org.gnome.Calendar
• org.gnome.clocks
• org.gnome.GTG
• org.gnome.Epiphany.Devel
• com.github.tchx84.Flatseal

[felipehw]

Is this a problem yet? I'm using Fedora 33 and everything works here.

[jurf]

Still is a problem, and has been since F32, maybe sooner.

I’ve been able to narrow it down to the --socket=fallback-x11 permission.

[BrainBlasted]

Seems like this happens if you start a wayland session, log out, then start an X11 session.

[fushinari]

@BrainBlasted seems to be right. Just tested on Arch. Logged into an X11 session, works fine. Logged into a Wayland session, works fine. Logged into an X11 session again, doesn't work anymore.

[MightyCreak]

I do have the issue as well on my app: Diffuse (on Fedora 33).

Although I have the option --socket=fallback-x11, it works on Wayland, but not on Xorg.

Edit: I concur with @BrainBlasted (I forgot I didn't reboot since I changed the X server), after a reboot my app runs again properly.

[jurf]

Yeah, a restart fixes it here too.

[jurf]

This has become a considerable annoyance because I frequently change between Xorg and Wayland as some apps have problems screen-sharing under Wayland. I’d gladly help if there is a way I can.

[X-m7]

In my case (Fedora Silverblue 33) I didn't need to reboot to fix it, logging out and back in with X11 again works.

[X-m7]

Also I noticed in flathub/flathub#1985 a bug regarding getting GDM/GNOME to clean up Wayland sockets on logout has been reported in https://gitlab.gnome.org/GNOME/gnome-session/-/issues/75, the maintainer there noticed that Flatpak apparently has wayland-0 hardcoded as a fallback below:

flatpak/common/flatpak-run.c

Lines 259 to 261 in acb2a19

	wayland_display = g_getenv ("WAYLAND_DISPLAY");
	if (!wayland_display)
	wayland_display = "wayland-0";