Cannot set LightDM Background / i3 Wallpaper

In previous versions of Qubes, I have been able to reliably set the lightdm background and i3 wallpaper by removing and re-linking /usr/share/backgrounds/default.png to some screenshotted image I liked.

Since fresh-installing R4.1.1, this behavior no longer works. LightDM flashes the new wallpaper briefly, and then fall back to the old drab Qubes_Steel background. Downstream, i3 can no longer rely on this technique.

So here are my specific questions:

  1. How can I reliably set the lightdm background without it falling back to Qubes_Steel?

  2. For setting i3 wallpaper, should I just rely on a utility like feh?

  3. What is the default QubesOS path that /usr/share/backgrounds/default.png link to? I’d prefer to set it back to the system default.

Check if the background option in /etc/lightdm/lightdm-gtk-greeter.conf is commented or not.

Eventually you could try to change it to a different path.

This is also something i tried, with the same result. The new wallpaper appears briefly on the lightdm greeter login screen, and then quickly fades out to be replaced with the default Qubes_Steel background.

For i3, I just opted to install feh.

Have you tried changing the background path in the .conf file and then running systemctl restart lightdm ?

Same result.

Apologies for the basic questions, just ruling things out. You’ve logged out after restarting the service, right?

If you run systemctl status lightdm do you see any errors?

Yes, I have logged out. Status check gives no errors.

Try this:

  1. edit /etc/lightdm/lightdm-gtk-greeter.conf and make sure that background=/usr/share/backgrounds/default.png is not commented out, and there are no other uncommented backround= parameters.
  2. Run ls -l /usr/share/backgrounds/default.png and check where it links to.
  3. Try to remove and/or replace that file with your image (make a backup first)

The link should be /usr/share/wallpapers/Qubes_Steel/contents/images/<resolution>.png

Per my OP, this is extremely similar to what I first attempted. The difference in your solution is to replace the soft link with an actual file. Nonetheless I did try it, to be thorough, and got the same result. The image flashes briefly at lightdm greeter login, and then fades Qubes_Steel back in.

Receipts:


Gasp! it’s…it’s…

This “fading” to the default Qubes background seems to be a “transition” between backgrounds, because when I set the transition-duration (in /etc/lightdm/lightdm-gtk-greeter.conf) to something like 5000 (milliseconds), the fade happens 5 seconds after LightDM loads.

I don’t know why this transition is enabled and can’t find anything on how to disable it. So I just set transition-duration to 2 minutes (120000 milliseconds), which is long enough that I won’t ever see the fade.

Update: this workaround works for setting the LightDM background, but once I log in, the background switches to the default qubes steel. It switches to the wallpaper I have set once my window manager loads.

Recommend installing feh to handle the wallpaper if you’re using i3. I’ve changed my lightdm settings also, then i3/feh kicks in… all good.