I believe this is related to https://bugs.gentoo.org/show_bug.cgi?id=625954 GDM update to 3.24 series has created gdm.service in /lib/systemd/system/gdm.service, while the systemd link still remains as /etc/systemd/system/display-manager.service -> /usr/lib64/systemd/system/gdm.service. /usr/lib64/systemd/system/gdm.service does not exist on my system. GDM does not start after system reboot, probably caused by this?
That's unlikely to be the problem. systemd only reads the name of the symlink, not the target. Check if there's some actual problem, like does systemctl status gdm.service say anything about that launch try or journalctl or some such.
I suffered from the same issue and disabling then enabling gdm.service then NetworkManager.service seems to have solved the issue. I cannot comment on why. I had already disabled/enabled gdm (not sure if I rebooted then), then looked at /etc/systemd/system and noticed wrong symlinks for NetworkManager and dependencies, so I did disable/enable it. After reboot, gdm starts.
I did disable the gdm service then re-enabled it, it seems to have corrected/updated the symlink. gdm is now starting successfully on boot.
Bug has been referenced in the following commit: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=047d52561eb214973360b3682ff983733b60fd87 commit 047d52561eb214973360b3682ff983733b60fd87 Author: Mike Gilbert <floppym@gentoo.org> AuthorDate: 2017-08-28 22:25:10 +0000 Commit: Mike Gilbert <floppym@gentoo.org> CommitDate: 2017-09-03 01:14:43 +0000 gnome-base/gdm: call systemd_reenable from postinst Bug: https://bugs.gentoo.org/628454 Package-Manager: Portage-2.3.6_p39, Repoman-2.3.3_p17 gnome-base/gdm/gdm-3.22.3-r1.ebuild | 2 ++ gnome-base/gdm/gdm-3.24.2.ebuild | 2 ++ 2 files changed, 4 insertions(+)
