System Settings > LightDM Crashes

[NoWorries]

I have two computers with Utopic installed on both. On my Laptop, when I select System Settings > Login Screen (LightDM), System Settings crashes. When I launch it from Konsole, I get the following:

XXXX@basil:~$ systemsettings
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.
Bus::open: Can not get ibus-daemon's address. 
IBusInputContext::createInputContext: no connection to ibus-daemon 
XXXX@basil:~$ true 
*** Error in `systemsettings': double free or corruption (fasttop): 0x0000000001546390 ***
KCrash: Application 'systemsettings' crashing...
KCrash: Attempting to start /usr/lib/kde4/libexec/drkonqi from kdeinit
sock_file=/home/aurora/.kde/socket-basil/kdeinit4__0
QSocketNotifier: Invalid socket 10 and type 'Read', disabling...
Unable to start Dr. Konqi
Re-raising signal for Apport handling.

When I try to lodge a fault report it fails because of insufficient debug information. This always happens without fail.

I tried the same procedure on a Compaq All-in-One and it worked correctly with the command line output being:

XXXX@manuel:~$ systemsettings
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.
Bus::open: Can not get ibus-daemon's address. 
IBusInputContext::createInputContext: no connection to ibus-daemon 
XXXX@manuel:~$ true 
loading themes 
("/usr/share/kde4/apps/lightdm-kde-greeter/themes/") 
"/usr/share/kde4/apps/lightdm-kde-greeter/themes/classic/theme.desktop" 
"adding theme" " Classic" 
"/usr/share/kde4/apps/lightdm-kde-greeter/themes/userbar/theme.desktop" 
"adding theme" "User Bar"

Does anyone have any ideas as to how to fix this problem or should I try an alternative approach to file a bug report?

[ronw]

No specific ideas for a fix, but that socket file for aurora sticks out as potential problem.

[oshunluvr]

Try it with another user. Could be a corruption in your home.

[NoWorries]

I have just tried logging in as Guest and LightDM crashed in the same way.

What I have found of interest is that I was trying to resolve my problems with the Nvidia driver not working as it should, so I installed KDM. This then resulted in not being able to activate the Nvidia option and I could only use my Intel graphic's card. So from this experience, I suspect that the Display manager impacts on the Nvidia performance and the fact that System Settings > LightM crashes, makes me wonder if there is something amiss in LightDM on my system.

Edit:

I just tried copying my .kde directory to .kde_bk and then removed .kde. After rebooting I then had a new .kde directory and when I tried System Settings > LightDM, its behaviour was as before, ie it CRASHED!!!

[oshunluvr]

Well, that's not it. You're likely on the right path - video drivers. It seems a lot of people are having trouble with dual (or is it duel?) video card laptops.

[NoWorries]

Thanks for your reply. I am wondering who I should have a "duel" with about the problems with dual video cards?

I am sure that there are many Laptops that have dual video cards to conserve power when operating only on battery. This problem needs to be fixed as my M$ Windows friends are critical of the lack of HDMI support with Linux.

[otisklt]

I did not think that dual vid card laptops have been around very long... Got one for someone recently but the card switching did not work... trying to access the nvidia settings with preview crashed it under win8. So I had to troubleshoot an issue with one from a popular vendor recently and their "support" diagnosed the problem like it was a single card system... running a simple benchmark app that I could not verify was capable of testing a dual card system specifically and they sent it back saying it was fine. No the switching problem was still there so the solution was to use the hardware manufacturer to get it fixed... it was a card/mb problem.

So long way around to tell you that you are likely stuck with forcing your system one way or the other until better driver support is available.
Meaning force only nvidia by config or power options or something.

[NoWorries]

I am pleased to report that the developers have now fixed lightDM which was updated on the 10 October with version 1.12.1

Thank You Developers

[SteveRiley]

I think we'd all be better off returning to KDM (bloated that it may be) and waiting for a usable version of SDDM to emerge. We are, after all, running KDE; seems reasonable to lessen complexity a bit by using our DE's preferred display manager rather than something designed by Canonical for primarily their own use.

[NoWorries]

I have found that with KDM, I cannot select the NVIDIA card, it only allows the use of my Intel card. I hope that SDDM comes out soon as with lightDM, it allows me to select the NVIDIA card, but I do not get a login screen. I have to type in my password and then my system starts with the NVIDIA card being used.

[SteveRiley]

Hm. What do you mean by "cannot select the NVIDIA card"? KDM doesn't offer any kind of graphics card selection mechanism. Is it that, with the NVIDIA card selected in your firmware, KDM won't render on the screen?

[NoWorries]

Hi Steve,

When I use lightDM, the NVIDIA X Server Settings look like this and I can either select the NVIDIA or the Intel cards.


When I use KDM, I get a minimalist NVIDIA X Server Settings that, no matter what I do, it always stays with the Intel card even after selecting the NVIDIA card. The KDM, NVIDIA Settings look like this:


As you can see it is totally different to what I get with lightDM. I just hope that SDDM solves this problem as I am sure the Ubuntu users do not have the problems that I am having with the NVIDIA card.

My BIOS gives no option to select a video card on boot.

[otisklt]

Is good to see some support for this configuration hitting linux

[OneLine]

DM status

Harald Sitter commented: https://bugs.launchpad.net/ubuntu/+s...e/+bug/1281036

...KDM is semi-unmaintained...

but I don't think that the LightDM KDE greeter status is better (?).