Arch Linux

Rob_H

Member

Registered: 2012-06-19

Posts: 72

[SOLVED] KDE Start New Session doesn't work from lock screen

On my laptop, if I lock the KDE 4 session and then click Switch Users > Start New Session, I get a login screen and can log in as a different user. All good.

If I do the same thing on my desktop, it doesn't work. When I click Switch Users > Start New Session, it doesn't start a new session or switch VTs. Instead, I just get reprompted for the existing user's password.

Both machines are running fully updated Arch. Anyone know how I can troubleshoot this? The only difference I can think of between the laptop and desktop is that the desktop has nomodeset specified as a kernel boot parameter. (It won't boot without it.) Could this be interfering with automatic VT switching? Manual VT switching (e.g. Ctrl+Alt+F1) works fine.

Last edited by Rob_H (2014-12-27 14:28:06)

Rob_H

Member

Registered: 2012-06-19

Posts: 72

Re: [SOLVED] KDE Start New Session doesn't work from lock screen

Little more detail. Checking the journal, I can see Xorg is failing to start on display :1. If I compare Xorg.0.log with Xorg.1.log, it appears that it's not finding the proprietary NVIDIA driver in the second case. Don't know why it would be any different for :1, though. See?

Xorg.0.log (good):

...
[    10.219] (II) LoadModule: "glx"
[    10.220] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[    10.293] (II) Module glx: vendor="NVIDIA Corporation"
[    10.293]    compiled for 4.0.2, module version = 1.0.0
[    10.293]    Module class: X.Org Server Extension
[    10.294] (II) NVIDIA GLX Module  343.36  Mon Dec  1 15:50:02 PST 2014
[    10.294] (II) Applying OutputClass "nvidia" to /dev/dri/card0
[    10.294]    loading driver: nvidia
[    10.294] (==) Matched nvidia as autoconfigured driver 0
[    10.294] (==) Matched nouveau as autoconfigured driver 1
[    10.294] (==) Matched nv as autoconfigured driver 2
[    10.294] (==) Matched nouveau as autoconfigured driver 3
[    10.294] (==) Matched nv as autoconfigured driver 4
[    10.294] (==) Matched modesetting as autoconfigured driver 5
[    10.294] (==) Matched fbdev as autoconfigured driver 6
[    10.294] (==) Matched vesa as autoconfigured driver 7
[    10.294] (==) Assigned the driver to the xf86ConfigLayout
[    10.294] (II) LoadModule: "nvidia"
[    10.294] (II) Loading /usr/lib/xorg/modules/drivers/nvidia_drv.so
[    10.300] (II) Module nvidia: vendor="NVIDIA Corporation"
[    10.300]    compiled for 4.0.2, module version = 1.0.0
[    10.300]    Module class: X.Org Video Driver
...

Xorg.1.log (bad):

...
[  2153.825] (II) LoadModule: "glx"
[  2153.825] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[  2153.833] (II) Module glx: vendor="NVIDIA Corporation"
[  2153.833]    compiled for 4.0.2, module version = 1.0.0
[  2153.833]    Module class: X.Org Server Extension
[  2153.833] (II) NVIDIA GLX Module  343.36  Mon Dec  1 15:50:02 PST 2014
[  2153.833] (==) Matched nouveau as autoconfigured driver 0
[  2153.833] (==) Matched nv as autoconfigured driver 1
[  2153.833] (==) Matched modesetting as autoconfigured driver 2
[  2153.833] (==) Matched fbdev as autoconfigured driver 3
[  2153.833] (==) Matched vesa as autoconfigured driver 4
[  2153.833] (==) Assigned the driver to the xf86ConfigLayout
[  2153.833] (II) LoadModule: "nouveau"
[  2153.833] (WW) Warning, couldn't open module nouveau
...

Any idea what would cause it to work for :0 but fail for :1?

Legg83

Member

Registered: 2012-06-17

Posts: 6

Re: [SOLVED] KDE Start New Session doesn't work from lock screen

I came here today to ask the same question. I have the exact same problem, also with an nvidia card on the desktop. I also have a laptop that does not have this problem but the laptop has an ati card/drivers. I suspected a problem with the latest nvidia driver update (343.36-2) so I attempted to downgrade to the last working nvidia driver I had (343.22) but could not get X to start. Now I'm back on 343.36 and the problem remains.

Edit:

I am wondering if this is related to xorg-server 1.16 rootless login now. Do you also see something similar to the following in your bad Xorg log?

[    33.875] (EE) systemd-logind: failed to get session: PID 1842 does not belong to any known session
[    33.876] (II) xfree86: Adding drm device (/dev/dri/card0)
[    33.876] (EE) /dev/dri/card0: failed to set DRM interface version 1.4: Permission denied

Last edited by Legg83 (2014-12-27 01:26:26)

Legg83

Member

Registered: 2012-06-17

Posts: 6

Re: [SOLVED] KDE Start New Session doesn't work from lock screen

Ok, I fixed my problem by downgrading xorg to 1.15. I mentioned my laptop did not have this problem and I discovered that was because in setting up my ati / catalyst drivers I had frozen xorg at version 1.15 for catalyst driver compatibility. I just downgraded to 1.15 on the desktop by using Vi0L0's xorg115 repository which is stuck on xorg 1.15.
https://wiki.archlinux.org/index.php/AM … st#xorg115

This is the problem: https://www.archlinux.org/news/xorg-ser … available/
In particular:

X is now rootless with the help of systemd-logind, this also means that it must be launched from the same virtual terminal as was used to log in, redirecting stderr also breaks rootless login. The old root execution behavior can be restored through the Xorg.wrap config file (man xorg.wrap). Please note that launching X through a login-manager (gdm, kdm, ...) doesn't yet provide rootless access.

You may have better luck with restoring the old root execution behavior through Xorg.wrap config file as eluded to in the blurb, but that did not seem to work for me.

Rob_H

Member

Registered: 2012-06-19

Posts: 72

Re: [SOLVED] KDE Start New Session doesn't work from lock screen

In my case, I am launching X via KDM and the Xorg.bin process is owned by root. Still, you may have set me on the right track. I'll keep poking. I'm noticing now that on the "bad" machine, Xorg is passed an extra argument: -novtswitch. That looks suspicious.

Rob_H

Member

Registered: 2012-06-19

Posts: 72

Re: [SOLVED] KDE Start New Session doesn't work from lock screen

Solved. As usual, the answer was on the wiki. Apparently, the problem is specific to the proprietary NVIDIA driver in conjunction with Xorg 1.16. Thanks for the help.

https://wiki.archlinux.org/index.php/xo … _Xorg_1.16

Last edited by Rob_H (2014-12-27 14:27:32)

Legg83

Member

Registered: 2012-06-17

Posts: 6

Re: [SOLVED] KDE Start New Session doesn't work from lock screen

Awesome. Worked for me too.