[SOLVED] XFCE4 not starting on GDM Wayland mode

Yusefz1 · 2022-12-16 03:36:20

Hello everyone, I just installed XFCE4 (package is called xfce4), then I selected All at the prompt, and GDM Wayland is unable to launch it, I click on XFCE4 in the session selection dialogue in GDM and a blank screen appears, then I am pushed back to the login screen.

Does anyone know why this is happening?

Is it maybe because of Wayland and Xorg conflicting? and will I have to use another DM like LightDM for it to work, I would prefer it more if I only had one display manager installed on the system rather than one just for XFCE4.

I have two DE's on my system: GNOME (which I installed first with GDM), and XFCE4 which I installed using GNOME, I only have one Display Manager on the system which is GDM.

Last edited by Yusefz1 (2022-12-20 00:39:36)

Yusefz1 · 2022-12-16 03:39:33

Found a post online about 13 years ago that has the same problem: https://forums.linuxmint.com/viewtopic.php?t=38067
Why has this issue not been fixed in 13 years.

Yusefz1 · 2022-12-16 03:43:22

Found a random hack that might fix it, idk if I want to try that: https://askubuntu.com/questions/1291585 … n-to-xfce4

seth · 2022-12-16 08:49:27

If that hack works, that's not a problem w/ GDM but the takedown of your session.
I'd start by looking at the system journal to figure *why* the login fails.

You're stressing the "wayland" part, do you not face the situation w/ https://wiki.archlinux.org/title/GDM#Use_Xorg_backend ?

Yusefz1 · 2022-12-16 17:04:38

seth wrote:

If that hack works, that's not a problem w/ GDM but the takedown of your session.
I'd start by looking at the system journal to figure *why* the login fails.
You're stressing the "wayland" part, do you not face the situation w/ https://wiki.archlinux.org/title/GDM#Use_Xorg_backend ?

I didn't try the hack because the simpler solution was to just install LightDM which works with XFCE but is unable to launch GNOME Wayland.
I should be able to launch XFCE through GDM Wayland mode, I haven't tested if it works in Xorg mode, because I need GNOME Wayland for its better gesture support on my laptops touchpad.

Last edited by Yusefz1 (2022-12-16 17:05:08)

Yusefz1 · 2022-12-16 17:06:56

seth wrote:

If that hack works, that's not a problem w/ GDM but the takedown of your session.
I'd start by looking at the system journal to figure *why* the login fails.
You're stressing the "wayland" part, do you not face the situation w/ https://wiki.archlinux.org/title/GDM#Use_Xorg_backend ?

I'm gonna test out GDM Wayland again and try to launch XFCE, but this time I'll post the logs here, anything specific I can look for?

Last edited by Yusefz1 (2022-12-16 17:07:10)

seth · 2022-12-16 17:19:25

Whatever happens after GDM kicks off the xfce session and looks like trouble.
And regardless, I'd *try* the GDM/Xorg behavior to narrow down whether it's a GDM or (GDM on) wayland related problem.

Yusefz1 · 2022-12-16 20:14:49

I have now tested GDM in Xorg mode and tried to launch XFCE, and it worked!
I switched GDM back into Wayland mode and now XFCE is suddenly able to launch, maybe the installation of LightDM added some needed dependencies? (I doubt it)

I did find something strange in journalctl that might of caused this (this bit is from before when it wasn't working with GDM in Wayland mode), I didn't really know what to look for, but this might be a clue:

Dec 16 03:28:40 arch-ideapad /usr/lib/gdm-x-session[14975]: xfce4-session: Another session manager is already running

I'm not going to mark this as solved yet because I don't know what caused the issue in the first place, and it could happen again.

But the good news is that now I can use GNOME Wayland and also XFCE without switching DM's from GDM to LightDM, if I find the problem I'm probably going to uninstall LightDM.

Last edited by Yusefz1 (2022-12-16 20:21:31)

seth · 2022-12-16 21:14:58

but this might be a clue

Not out of context, we'll need to see a journal covering the failing attempts - otherwise everyone elses magic 8-ball is as good as yours to speculate "what caused the issue in the first place".

Yusefz1 · 2022-12-16 23:08:44

seth wrote:

but this might be a clue
Not out of context, we'll need to see a journal covering the failing attempts - otherwise everyone elses magic 8-ball is as good as yours to speculate "what caused the issue in the first place".

Is there any way to get rid of sensitive information in the log files?

Yusefz1 · 2022-12-16 23:09:53

Or do you want the entire output of journalctl?

seth · 2022-12-17 07:51:56

The journal is not supposed to contain any actually sensitive data.
MACs and UUIDs are trackable (ie. if you post them in multiple locations, one can link those posts to the same individual) but are generally not sensitive
If for whatever reason you don't want to see your natural name in there, eg. because it's your login, you can replace it w/ "johndoe")

Yusefz1 · 2022-12-17 14:42:04

Okay, in that case I just left it alone, here's the journalctl logs from yesterday at 3AM to 4AM where it wasn't working (it has quite alot of lines), it also contains that error that I thought was a clue, but it could be something else: http://ix.io/4iPz
(FYI I had GDM in Wayland mode and was trying to launch XFCE, but it wouldn't work, maybe the logs have something in them about this problem.)

Last edited by Yusefz1 (2022-12-17 14:48:56)

seth · 2022-12-17 15:13:49

There's no obvious error or failure and in that case

Dec 16 03:28:48 arch-ideapad /usr/lib/gdm-x-session[15228]: xfce4-session: Another session manager is already running

Suggests that something™ seems to set or leak SESSION_MANAGER into the startxfce4 context, do you run a parallel session and/or did you log into a different session before (in particular gnome - try whether you can log into xfce4 directly after booting the system)

You can also try to edit /usr/bin/startxfce4 (or maybe shadow it in /usr/local/bin/startxfce4) and start w/ "unset SESSION_MANAGER" (or in the shadow case "unset SESSION_MANAGER; exec /usr/bin/startxfce4")

Yusefz1 · 2022-12-17 15:32:46

seth wrote:

There's no obvious error or failure and in that case
Dec 16 03:28:48 arch-ideapad /usr/lib/gdm-x-session[15228]: xfce4-session: Another session manager is already running
Suggests that something™ seems to set or leak SESSION_MANAGER into the startxfce4 context, do you run a parallel session and/or did you log into a different session before (in particular gnome - try whether you can log into xfce4 directly after booting the system)
You can also try to edit /usr/bin/startxfce4 (or maybe shadow it in /usr/local/bin/startxfce4) and start w/ "unset SESSION_MANAGER" (or in the shadow case "unset SESSION_MANAGER; exec /usr/bin/startxfce4")

I am able to login to XFCE with GDM Wayland straight after booting, as I mentioned before it now works, I did login to GNOME before launching XFCE IIRC, this was yesterday though, now everything somehow Just Works (TM).
I looked in my logs today, and that "Another session manager" error is not there (and I have been able to login to XFCE through GDM Waylandd), so maybe that has something to do with it?

Last edited by Yusefz1 (2022-12-17 15:35:05)

seth · 2022-12-17 15:40:16

I suspect/could imagine that something™ drops something™ somewhere™ where it gets sourced by the shell that executes startxfce4 and that something™ sets SESSION_MANAGER, but we'd need to face the situation to track it down.
If this fails the next time, log into a console (ctrl+alt+f2) and "echo $SESSION_MANAGER" there

Edit: also

tr '\0' '\n' < /proc/$PID/environ | grep -i session

w/ $PID whatever the various running GDM processes are at that time.

Last edited by seth (2022-12-17 15:42:59)

Yusefz1 · 2022-12-17 15:44:04

seth wrote:

I suspect/could imagine that something™ drops something™ somewhere™ where it gets sourced by the shell that executes startxfce4 and that something™ sets SESSION_MANAGER, but we'd need to face the situation to track it down.
If this fails the next time, log into a console (ctrl+alt+f2) and "echo $SESSION_MANAGER" there
Edit: also
tr '\0' '\n' < /proc/$PID/environ | grep -i session
w/ $PID whatever the various running GDM processes are at that time.

Will do, thanks for your help btw.

Yusefz1 · 2022-12-17 21:50:43

Update: I've found that the problem occurs after I use startx to manually launch a window manager, I could launch any window manager using startx and what would happen is I would start the display manager (GDM Wayland) again (because I have to stop the DM to use startx), and it would fail to login to XFCE, whereas before it would work, so maybe it has something to do with startx? Also after restart XFCE works again through GDM Wayland.

I ran this command:

tr '\0' '\n' < /proc/$PID/environ | grep -i session

Against processes with "gdm" in them, I found that out with:

pgrep -a gdm

So this is a list of processes and what that command outputted for each of them:
gdm:
The command didn't return anything.
gdm-wayland-session:

XDG_SESSION_CLASS=greeter
XDG_SESSION_TYPE=wayland
XDG_SESSION_ID=27
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/120/bus
GDM_SUPPORTED_SESSION_TYPES=wayland:x11

gdm-session-worker:

GDM_SESSION_DBUS_ADDRESS=unix:abstract=/tmp/dbus-H1oBRK3c

Last edited by Yusefz1 (2022-12-17 21:57:26)

Yusefz1 · 2022-12-17 21:51:48

Also in the TTY, after doing ctrl-alt-f2 and doing:

echo $SESSION_MANAGER

Nothing was returned.

Last edited by Yusefz1 (2022-12-17 21:56:13)

seth · 2022-12-18 16:17:02

Did you end the session run w/ startx before re-starting GDM to login from there?
Even if, are there processes from that session still lingering around?
Do you systemctl start the GDM service or run gdm directly (from within the shell that ran startx before)?

Yusefz1 · 2022-12-18 16:30:03

seth wrote:

Did you end the session run w/ startx before re-starting GDM to login from there?
Even if, are there processes from that session still lingering around?
Do you systemctl start the GDM service or run gdm directly (from within the shell that ran startx before)?

Yes I did, ended it (Xorg) with Ctrl-C, then I started the display manager service (display-manager.service, which was a symlink to the gdm service) using the systemctl start command (from the same TTY that I did startx in), I didn't start GDM manually using the gdm command.

I don't think anything was lingering, if there was I would be surprised because I ended the startx command (which was running in the foreground in the TTY that I started it in) with a Ctrl-C and it should've killed Xorg along with other processes stemming from Xorg which I'm sure it did.

Last edited by Yusefz1 (2022-12-18 16:47:57)

seth · 2022-12-18 21:04:28

Any disowned non-X11 process could survive.
However, please post your xinitrc and compare the tmpfs (/tmp and /run) before and after the startx call.
If the shell doesn't get contaminated and a reboot "fixes" it, maybe the startx session leaves some bogus runtime file behind.

Yusefz1 · 2022-12-19 00:49:50

seth wrote:

Any disowned non-X11 process could survive.
However, please post your xinitrc and compare the tmpfs (/tmp and /run) before and after the startx call.
If the shell doesn't get contaminated and a reboot "fixes" it, maybe the startx session leaves some bogus runtime file behind.

Okay, so I did an ls on the directories before and after I did the startx command, then diffed them, and put diffs of both directories into the same file.

This is my xinitrc: http://ix.io/4iYq
This is the differences in /run and /tmp before and after running startx (after meaning when I've killed it from the TTY it was started in after it has started): http://ix.io/4iYp

Last edited by Yusefz1 (2022-12-19 00:55:54)

seth · 2022-12-19 10:11:23

To be clear, you startx, then end that session and are left w/ /tmp/.ICE-unix/3306 ?
Try to remove that file before starting GDM.
Anything else in /tmp/.ICE-unix at any point?

Edit: 3306 is a PID, you could try to log "ps aux" to figure what it belonged to
Though if it's only added w/ the termination, it might be some short lived process and hard to track.

I'll through a curveball: emacs?

Last edited by seth (2022-12-19 10:15:59)

Yusefz1 · 2022-12-19 21:26:29

Yes, there is still files in that directory after killing the startx command.
I've tried to delete the files in this directory and start the DM service again, but XFCE still fails to launch on GDM Wayland, and only works straight after restart and after that, it fails to work.

After 4 days of trying to find out what the issue is, I still have no clue what the problem is, I think it is a waste of time to keep trying to find the problem, and I haven't found much similar issues on the web or on these forums:
- This one is from ages ago: https://forums.linuxmint.com/viewtopic.php?t=38067
- And this one sounds related but this guys problem was with his graphics drivers, I know that that isn't the problem I have: https://bbs.archlinux.org/viewtopic.php … 9#p1733279

I might just reinstall (probably not needed though) or use LightDM instead, or not use a DM at all, because I'm fed up with it not working, thanks for helping me.

Last edited by Yusefz1 (2022-12-19 21:35:09)

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#1 2022-12-16 03:36:20

[SOLVED] XFCE4 not starting on GDM Wayland mode

#2 2022-12-16 03:39:33

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#3 2022-12-16 03:43:22

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#4 2022-12-16 08:49:27

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#5 2022-12-16 17:04:38

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#6 2022-12-16 17:06:56

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#7 2022-12-16 17:19:25

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#8 2022-12-16 20:14:49

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#9 2022-12-16 21:14:58

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#10 2022-12-16 23:08:44

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#11 2022-12-16 23:09:53

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#12 2022-12-17 07:51:56

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#13 2022-12-17 14:42:04

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#14 2022-12-17 15:13:49

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#15 2022-12-17 15:32:46

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#16 2022-12-17 15:40:16

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#17 2022-12-17 15:44:04

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#18 2022-12-17 21:50:43

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#19 2022-12-17 21:51:48

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#20 2022-12-18 16:17:02

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#21 2022-12-18 16:30:03

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#22 2022-12-18 21:04:28

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#23 2022-12-19 00:49:50

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#24 2022-12-19 10:11:23

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

#25 2022-12-19 21:26:29

Re: [SOLVED] XFCE4 not starting on GDM Wayland mode

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