No dm after upgrade

[doctordruidphd]

Did the upgrade from 12.04. Usual potholes, no really drastic problems.

Until I rebooted. X is not starting. Trying to start kdm, just does nothing. Gives a message saying kdm start/running, but no X. Trying to start lightdm, kicks in the video driver, but still no X. Nothing in Xorg.0.log.

I am using the nvidia-current driver, which installed without errors.

Did I miss something obvious, like kdm or X no longer supported?

I would try reverting to nouveau, but the problem seems to be elsewhere than the driver itself.

[james147]

First try this:

sudo apt-get update                   # Get the latest package list
sudo apt-get install -f               # Fix any broken packages
sudo apt-get dist-upgrade             # Update any out of date packages
sudo apt-get install kubuntu-desktop  # Make sure everything you need is installed

[doctordruidphd]

Uhh, yeah, that's basically how one does a system upgrade, after modifying everything in sources.list and sources.list.d.

Everything installed, everything current.

Nonetheless, dpkg-reconfigured both kdm and lightdm, made no difference. Neither will start, no matter which is configured as the default dm. lightdm is trying to start, it engages the video driver (the fans slow down), but never actually appears. No errors in Xorg.0.log, very strange. Got to be some more basic configuration problem.

[doctordruidphd]

Stranger and stranger:

Running startx brings up kde. But how? kdm is not running, nor is lightdm.

[SteveRiley]

A display manager isn't required to run X.

[doctordruidphd]

OK, so:

sudo service kdm start

is no longer useful for starting kde? Apparently the system is trying to start kde that way, but it isn't working. Since others don't seem to be having this problem, I imagine something in the upgrade didn't work right. Any ideas what? I seem to be in the dark about some changes that have occurred; are these documented somewhere?

Thanks for any info. The system seems to work right once started manually with startx, but I don't know why it isn't starting up by itself.

[SteveRiley]

Some random thoughts...

* Anything unusual in .xsession-errors?
* What's in /var/log/kdm.log and /var/log/kdm.log.1?
* What's in /etc/X11/default-display-manager?
* What might grep -i kdm /var/log/* reveal?

[doctordruidphd]

* Anything unusual in .xsession-errors?

Strange, there is no ~/.xsession-errors file.

* What's in /var/log/kdm.log and /var/log/kdm.log.1?

Yep, there's a problem:

Fatal server error:
Unrecognized option: -nr

I looked around, and found this command in /etc/kde4/kdm/kdmrc:

[X-:*-Core]
AllowNullPasswd=true
AllowShutdown=All
NoPassEnable=false
NoPassUsers=
ServerArgsLocal= -nr -nolisten tcp ### <-OOPS!
ServerCmd=/usr/bin/X

I rubbed out the -nr part and tried starting again, got the same error. Which means the problem is coming from a startup script somewhere, not kdmrc. Will look through init.d and rc*.d and /etc/X11 to see if I can find it, though I have to say I remain befuddled by how upstart does things.

This does appear to be a valid option in 12.04, it's in kdmrc and kdm starts up fine. Another reason to suspect it isn't coming from there.

* What's in /etc/X11/default-display-manager?

kdm

* What might grep -i kdm /var/log/* reveal?
will work through #2 above then look at this, though nothing in dmesg at this point.

Thanks for the suggestions.

[doctordruidphd]

Update: I have not been able to figure out how kdm is being started during bootup. Even after changing kdmrc, the error message persists, and kdm crashes immediately after being invoked. So, the present status is I get no login screen, only tty1. Once I log in, I can do startx, and kde comes up, apparently normal. So what needs fixing is the process that leads to the login screen. Doing a reinstall on kdm did not fix it.

Thanks for any further suggestions.

Further:

* What might grep -i kdm /var/log/* reveal?

Several of these:

syslog:Aug 30 06:05:29 localhost kdm[4861]: X server died during startup
syslog:Aug 30 06:05:29 localhost kdm[4861]: Failed to start X server. Starting failsafe X server.
syslog:Aug 30 06:05:29 localhost kdm[4874]: Cannot execute "/etc/gdm/failsafeXServer": No such file or directory

However, no indication of a problem in Xorg.0.log

[james147]

Update: I have not been able to figure out how kdm is being started during bootup. Even after changing kdmrc, the error message persists, and kdm crashes immediately after being invoked. So, the present status is I get no login screen, only tty1. Once I log in, I can do startx, and kde comes up, apparently normal. So what needs fixing is the process that leads to the login screen. Doing a reinstall on kdm did not fix it.

Thanks for any further suggestions.

kdm is started by upstart during boot, which can be started manually via upstart with "sudo service kdm start". startx is basically what kdm calls (as your user) after you authenticate your username and password with it and you can call it manually without kdm if you need to (kdm is just a nicer way to login then logging in via comandline and typing startx and so is completely optional).

That said I am surprised that removing the -rn flags in kdmrc did not remove or at least change the error message, looking at my kdmrc it does not have the -rn flags either.

ServerArgsLocal=-nolisten tcp

is what I have in mine, note that the lack of a space between the = and - might be important.

[ronw]

Cannot execute "/etc/gdm/failsafeXServer": No such file or directory

kdm is looking at a gdm config directory? Maybe kdm is set to "use previous session" and is dying because the Gnome DM isn't installed?

[doctordruidphd]

What I suspect is there's another script involved that I haven't found yet. Will mess with it again later today. What's really strange is that none of the dm's I have installed -- kdm, lightdm, or even xdm -- want to start up. I really suspect that when I zapped the unity desktop from the system, it pulled off something that really needed to be there.

kdm is looking at a gdm config directory? Maybe kdm is set to "use previous session" and is dying because the Gnome DM isn't installed?

That's a good possibility, will check on it.

[oshunluvr]

My kdmrc has

ServerArgsLocal=-br -nolisten tcp

The variances are strange.

[doctordruidphd]

solved.

did an apt-get install --reinstall on kdm. For some unknown reason, it did not overwrite the existing kdmrc, but it did put the new file in as kdmrc-dpkg-dist. So I moved the old kdmrc out of the way, did the rename, and now it is coming up. The new one file has only:

ServerArgsLocal=-nolisten tcp

Since I already tried that, something somewhere else must also have been reset.

Thanks for all of the suggestions. Probably never figure out exactly what happened, but it works (for now).

[SteveRiley]

My kdmrc has this:

ServerArgsLocal=-br -nolisten tcp

From man xserver:

OPTIONS

       {...snip...}

       -br     sets the default root window to solid black instead of the standard root
               weave pattern. This is the default unless -retro or -wr is specified.

I'm thinking that the "-nr" you had snuck in as a typo at some point, given that "b" and "n" are next to each other on the keyboard. But it doesn't explain the problem you had.