How to start fvwm window manager for own created target

Question

I'm running debian bullseye (with mate desktop) on lenovo T430. For only playing in pcsxr I want to create an own systemd target (called pcsxr.target) because I have not much memory.

Current state:

cat /etc/systemd/system/pcsxr.target
# pcsxr.target

[Unit]
Description=pcsxr.target 
Wants=fvwm.service
After=multi-user.target rescue.service rescue.target
Conflicts=rescue.target rescue.service 
AllowIsolate=yes

Following services I linked to pcsxr.target.wants

ls -al /etc/systemd/system/pcsxr.target.wants/
insgesamt 8
drwxr-xr-x  2 root root 4096 11. Apr 12:33 .
drwxr-xr-x 14 root root 4096 11. Apr 12:31 ..
lrwxrwxrwx  1 root root   32 10. Apr 13:39 dbus.service -> /lib/systemd/system/dbus.service
lrwxrwxrwx  1 root root   31 10. Apr 14:25 dbus.socket -> /lib/systemd/system/dbus.socket
lrwxrwxrwx  1 root root   30 11. Apr 12:33 fvwm.service -> /etc/systemd/user/fvwm.service
lrwxrwxrwx  1 root root   34 10. Apr 13:38 systemd-user-sessions -> /lib/systemd/systemd-user-sessions
lrwxrwxrwx  1 root root   35 10. Apr 13:40 udisks2.service -> /lib/systemd/system/udisks2.service

And

cat /etc/systemd/user/fvwm.service 
#standalone fvwm für pcsxr
[Unit]
Description=standalone fvwm für pcsxr
Requires=basic.target
After=systemd-user-sessions.service sound.target
Conflicts=rescue.service rescue.target
After=basic.target rescue.service rescue.target



[Service]
User=alex
Group=alex
PAMName=login
#TTYPath=/dev/tty1
ExecStart=/usr/bin/fvwm2 -f /usr/share/fvwm/default-config/.stalonetrayrc -d :0
Restart=on-abort
StandardInput=tty

[Install]
WantedBy=pcsxr.target

When I try boot up this target over grub; the last message I see is

reached pcsxr.target

but now window manger starts.

Then I thougt maybe a problem with env ($DISPLAY)

cat .config/environment.d/fvwm-env.conf 
Environment="DISPLAY=:0"

my goal ist:

boot up pcsxr.target with window manager fvwm. Without involving lightdm (display-manager) if possible.

Thanks for reading.

Answer 1

Okay got it.

For the first I made am mistake in

/etc/systemd/system/pcsxr.target.wants/

The correct link is not

systemd-user-sessions -> /lib/systemd/systemd-user-sessions

it is

ls -l /etc/systemd/system/pcsxr.target.wants/
insgesamt 0
lrwxrwxrwx 1 root root 32 10. Apr 13:39 dbus.service -> /lib/systemd/system/dbus.service
lrwxrwxrwx 1 root root 31 10. Apr 14:25 dbus.socket -> /lib/systemd/system/dbus.socket
lrwxrwxrwx 1 root root 32 22. Aug 12:56 fvwm.service -> /etc/systemd/system/fvwm.service
lrwxrwxrwx 1 root root 53  7. Sep 19:03 systemd-user-session.service -> /usr/lib/systemd/system/systemd-user-sessions.service  # I mean this one
lrwxrwxrwx 1 root root 35 10. Apr 13:40 udisks2.service -> /lib/systemd/system/udisks2.service

Then finally I got an an error message in

/home/alex/.local/share/xorg/Xorg.0.log.old

(EE) parse_vt_settings: Cannot open /dev/tty0 (Permission denied)

Then I changed in

    /etc/X11/Xwrapper.config 

    needs_root_rights=yes