[Solved] PGTK Emacs launchs in Xwayland on KDE Plasma Wayland session

harmony · 2023-10-17 16:24:49

From Alacritty, running on wayland:

➜ pacman -Q | rg emacs
emacs-wayland 29.1-4

➜ echo $XDG_SESSION_TYPE
wayland

➜ echo $WAYLAND_DISPLAY
wayland-0

I can see that Kwin and Alacritty do run in wayland, verified with xlsclients, xwininfo, and the kwin debug console (qdbus org.kde.KWin /KWin org.kde.KWin.showDebugConsole) but when I launch emacs from the same terminal, or from the Plasma launcher, I get this message in a separate window: (I also disabled my config by launching emacs with -q)

You are trying to run Emacs configured with the "pure-GTK" interface under the X Window System. That configuration is unsupported and will lead to sporadic crashes during transfer of large selection data. It will also lead to various problems with keyboard input.

Inside emacs I've checked XDG_SESSION_TYPE and WAYLAND_DISPLAY with M-x getenv, and they report the same as from Alacritty.

I believe this behaviour started when I added packages and configuration for Hardware Video Acceleration

https://wiki.archlinux.org/title/Hardwa … celeration

I have a new AMD laptop with integrated graphics and configured radeonsi .

I'm not sure why that might be related, but other than package updates that was the only change I can think of.
Any suggestions appreciated.

Solved: Careful what global env you set for your display manager

Last edited by harmony (2023-10-17 17:47:34)

seth · 2023-10-17 17:19:36

Does emacs spark an xwayland instance, resp. does it run if you remove xwayand?
Does its window show up in "xwininfo -root -tree"?

harmony · 2023-10-17 17:23:42

seth wrote:

Does emacs spark an xwayland instance, resp. does it run if you remove xwayand?
Does its window show up in "xwininfo -root -tree"?

Yes, emacs shows as running via xwayland in xwininfo and xlsclients.

➜ xwininfo -root -tree | rg Emacs -A 5 -B 5

  Root window id: 0x3e1 (the root window) (has no name)
  Parent window id: 0x0 (none)
     51 children:
     0x3e00016 (has no name): ()  1x1+-1+-1  +-1+-1
     0x3e00001 "emacs": ("emacs" "Emacs")  10x10+10+10  +10+10
--
     0x200002 "KWin": ()  1x1+0+0  +0+0
     0x200025 (has no name): ()  896x964+944+361  +944+361
        1 child:
        0x200026 (has no name): ()  896x936+0+28  +944+389
           1 child:
           0x3e0001f "*scratch* - GNU Emacs at thinky": ("emacs" "Emacs")  896x936+0+0  +944+389
              1 child:
              0x3e00020 (has no name): ()  1x1+-1+-1  +943+388
     0x200022 (has no name): ()  2188x760+186+318  +186+318
        1 child:
        0x200023 (has no name): ()  2188x732+0+28  +186+346
           1 child:
           0x3e00003 "Warning": ("emacs" "Emacs")  2188x732+0+0  +186+346
              1 child:
              0x3e00004 (has no name): ()  1x1+-1+-1  +185+345
     0x20001d (has no name): ()  2560x1396+0+0  +0+0
        1 child:
        0x20001e (has no name): ()  2560x1396+0+0  +0+0

➜ xlsclients | rg emacs
thinky  emacs

Is there any way to remove or disable Xwayland without removing plasma? It seems to be a dependency.

➜ sudo pacman -R xorg-xwayland
checking dependencies...
error: failed to prepare transaction (could not satisfy dependencies)
:: removing xorg-xwayland breaks dependency 'xorg-xwayland' required by plasma-wayland-session

Last edited by harmony (2023-10-17 17:26:55)

seth · 2023-10-17 17:32:48

-Rdd, but since this isn't just a bogus message from emacs, that's also not required.
I assume the intention of using emacs-wayland is to run it using wayland.

Do you run emacs as daemon or https://wiki.archlinux.org/title/Emacs# … stemd_unit ?
Does it behave under eg. weston ?

harmony · 2023-10-17 17:46:42

Thanks for your help Seth, I discovered the issue.

Emacs launched as expected in weston.

I dug more into my environment config for plasma (~/.config/plasma-workspace/env/) and noticed I had foolishly set this variable globally:

export GDK_BACKEND=x11

I did this to ensure a small program would be able to make a systray icon, but setting this across my entire session had a pretty big effect, obviously.

Arch Linux

#1 2023-10-17 16:24:49

[Solved] PGTK Emacs launchs in Xwayland on KDE Plasma Wayland session

#2 2023-10-17 17:19:36

Re: [Solved] PGTK Emacs launchs in Xwayland on KDE Plasma Wayland session

#3 2023-10-17 17:23:42

Re: [Solved] PGTK Emacs launchs in Xwayland on KDE Plasma Wayland session

#4 2023-10-17 17:32:48

Re: [Solved] PGTK Emacs launchs in Xwayland on KDE Plasma Wayland session

#5 2023-10-17 17:46:42

Re: [Solved] PGTK Emacs launchs in Xwayland on KDE Plasma Wayland session

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