Arch Linux

jakalof

Member

Registered: 2020-05-15

Posts: 11

[Solved] GDM start fails after copy '/' to a new encrypted '/mnt'

I wanted to start using encryption for my arch system.

I got a new hard drive, encrypted a volume and used rsync to copy '/' to the new encrypted root file system mounted at /mnt

I’m using the "LVM on LUKS" approach.

After a lot of failures finally got it to boot but only in non-graphical. The wireless is working. The only thing (so far) that seems not to be working is the graphical GDM.

On the original un-encrypted system, GDM would not try to launch X. But on the encrypted system — GDM is launching X which seems to fail for some reason. I think the original system was using nouveau.

If I boot, I can login but only in non-graphical mode; then I do 'systemctl start gdm' and I get the dreaded flashing "_" in upper left corner; however, I can ssh to the system from another computer. So the system is up its just that GDM start is failing.

For the encrypted system: when I look in /mnt/var/log there is an 'Xorg.0.log' which shows a failure. For the UN-encrypted system: when I look in /var/log there is NO 'Xorg.0.log' or any 'Xorg.log'

Why is gdm launching X? Did I missing something in my rsync command that I need to fix or adjust?

I could use some suggestions? I don’t know to fix this? How can I tell the system to use nouveau rather than X? I’m using the exact kernel as on the original system which works fine. So something to do with the way I copied the system over and boot.

I used rsync with a lot of 'excludes' including the following list

#!/bin/bash

SRC=/
DEST=/mnt
EXCLUDES=$HOME/bin/root.exclude

rsync -aAXHv --delete --exclude-from=${EXCLUDES} $SRC $DEST

file root.exclude

- boot/*
- home/*
- dev/*
- proc/*
- sys/*
- tmp/*
- run/*
- mnt/*
- media/*
- lost+found

SOLVED:
Well -- the above 'exclude' list ended up excluding some modules which had 'media' in their path -- it was sort of a miracle that the system managed to boot and work as well as it did.  What gave me the clue was the 'nouveau' graphics driver was not getting loaded -- that was because the 'kms' module was not getting loaded -- which was caused by yet another lower level model not getting loaded and so on.  Once I realized that then I started messing around with the 'excludes' and using the 'rsync' option '--dry-run' and could see what was left out that was creating the issue.  The first clue came when I noticed that 'mkinitcpio -P' was having trouble finding the necessary modules.

Last edited by jakalof (2023-04-01 21:26:08)