No Display Manager in Kubuntu 16.04 After Upgrade From Kubuntu 15.10

[Stephen Morris]

On 02/06/16 08:39, Stephen Morris wrote:
> On 01/06/16 08:46, Clay Weber wrote:
>> On Wednesday, June 1, 2016 7:38:14 AM EDT Stephen Morris wrote:
>>> Hi,
>>>
>>>       After receiving notification that there was an upgrade for 
>>> Kubuntu
>>> available (not that I actually have Kubuntu installed, I have Ubuntu
>>> installed with KDE installed as an addon), I ran a sudo
>>> do-release-upgrade to undertake the upgrade. This process downloaded
>>> between 2500 - 2600 packages.
>>>
>>>       After the upgrade, when I boot into the os, the boot process 
>>> wants
>>> to start SDDM but the start fails, and every re-attempt to start it
>>> fails. Using systemctl to attempt to start the service manually fails
>>> with no meaningful messages, and systemctl status sddm.service doesn't
>>> show any meaningful messages either. If I issue the command, systemctl
>>> start lightdm.service, that starts the DM quite happily.
>>>
>>>       I have checked /etc/X11/default-display-manager and that had the
>>> command /usr/bin/lightdm as the display manager to launch, but that
>>> location in not the location where lightdm is installed. I have 
>>> replaced
>>> this command with /usr/sbin/lightdm, but on a reboot the boot process
>>> still tries to unsuccessfully load SDDM. I have also noticed that the
>>> location of SDDM, unlike Lightdm, is actually /usr/bin/sddm.
>>>
>>>       Is anyone able to shed some light on why the 16.04 boot wants to
>>> always start SDDM even though the default display manager is set to
>>> lightdm, and also why sddm cannot actually start? Could it be that the
>>> sddm.service process is looking for sddm in /usr/sbin when it is
>>> actually in /usr/bin, and if so, would a symlink in /usr/sbin back to
>>> /usr/bin/sddm rectify the issue?
>>>
>>> regards,
>>>
>>> Steve
>> My guess, not knowing exactly how you installed Plamsa desktop as an 
>> "addon"
>> would be that though sddm was installed it may not have been 
>> registered or
>> activated or whatever with systemd perhaps?  "meaningless" output might
>> actually be useful here.
> When I installed 15.10 I installed Ubuntu 15.10, then after 
> installation I installed ODE from the repositories as opposed to 
> actually installed Kubuntu 15.10. ODE was working fine in 15.10 with 
> lightdm as the display manager.
>>
>> $ sudo systemctl start sddm
>> shows nothing?
> Issuing this command just produces a message that it errored with 
> exit-code and status = 1/failed. It also produced messages that the 
> wait time was over and it was restarting the service, then a message 
> that Saddam had been stopped, followed by a message that a restart of 
> Saddam was attempted to soon. All 3 messages had exactly the same 
> timestamp.
> I could write the exact messages down and add them to the mail if we 
> need them. My mail system is running in Fedora, which is on the same 
> physical machine as Ubuntu, and I'm tri-booting between Windows 10, 
> Fedora and Ubuntu.
> One thing I have also noticed is that if the command sudo systemctl 
> status Saddam.service is issued the first thing it does is check 
> /etc/X11/default-display-manager to see if it contain /usr/bin/Saddam 
> and if so it says everything is ok and it can be used as a plugin to 
> another process(I'd need to check again exactly what this process is) 
> and if its not set to that it flags and error, but either way it 
> indicates that Saddam can't be started.
>>
>> You can try this to register sddm in systemd:
>>
>> $ sudo systemctl enable sddm.service -f
>>
>> You can also Try running
>>
>> $ sudo dpkg-reconfigure lightdm  ## or sddm
>>
>> this should bring up a dialog to choose which login manager to use as 
>> default.
>> You should be able to select lightdm which is the default for Ubuntu 
>> anyway.
> I issued the sudo dpkg-reconfigure command and that process put 
> /usr/bin/Saddam or /usr/sbin/lightdm into 
> /etc/X11/default-display-manager depending on which one was selected 
> as the default. Given that on my system 
> /etc/X11/default-display-manager had /usr/bin/lightdm it looks to me 
> like 16.04 has installed lightdm into a different location to where it 
> was in 15.10 and the upgrade has set /etc/X11/default-display-manager 
> to reflect the new location.
>>
>>
>> I am not sure if the  /etc/X11/default-display-manager specifies what 
>> happens
>> when you use the start x manually rather than what the init starts up.
> I'm not explicitly using startx manually. What I have now found after 
> using dpkg-reconfigure is that if the default dm is lightdm, the boot 
> process tries to start Saddam regardless, attempts six times to do so 
> and then gives up, dropping me into a console login prompt. If I login 
> and issue sudo systemctl start lightdm.service I get th e normal 
> lightdm login screen and then I can login to ODE quite happily.
> If I select Saddam as the default dm in dpkg-reconfigure the boot 
> process doesn't produce the errors and starts Saddam. The issue I get 
> at this point seems to vary from boot to boot, the first boot produced 
> a dialog saying that the graphics mode was too and I would need to 
> reconfigure the options (this sounds to me like the upgrade has not 
> upgraded the nvidia proprietary drivers I was using in 15.10 which 
> were installed from the repository), when I pressed enter because ok 
> was the only option, it then displayed a dialog with four radio 
> buttons on it, but I was unable to cycle through the buttons and enter 
> appeared to do nothing, so I couldn't go any further. The 2nd time I 
> booted Saddam started up to the normal blank screen it displays when 
> it is initializing, without any prompts of any kind, but went no 
> further. The 3rd time I booted it went through the same process as the 
> 1st boot with the same results.
>>
>> I have no idea where lightdm should go, but I doubt symlinking 
>> probably will
>> do nothing useful.
> When I did the upgrade I specified do-release-upgrade without any 
> parameters, could my issues be because I didn't explicitly tell it to 
> do a workstation upgrade? If this is the case can it be redone or do I 
> need to download a 16.04 DVD image and redo the install from scratch?
>
> regards,
> Steve
I have now issued command systemctl status sddm.service and received the 
following output:

systemctl status sddm.service
● sddm.service - Simple Desktop Display Manager
    Loaded: loaded (/lib/systemd/system/sddm.service; enabled; vendor 
preset: enabled)
    Active: inactive (dead) (Result: exit-code) since Fri 2016-06-10 
17:08:06 AEST; 2min 53s ago
      Docs: man:sddm(1)
            man:sddm.conf(5)
   Process: 1193 ExecStartPre=/bin/sh -c [ "$(cat 
/etc/X11/default-display-manager 2>/dev/null)" = "/usr/bin/sddm" ] 
(code=exited, status=1/FAILURE)

Jun 10 17:08:05 Home-Desktop systemd[1]: sddm.service: Failed with 
result 'exit-code'.
Jun 10 17:08:06 Home-Desktop systemd[1]: sddm.service: Service hold-off 
time over, scheduling restart.
Jun 10 17:08:06 Home-Desktop systemd[1]: Stopped Simple Desktop Display 
Manager.
Jun 10 17:08:06 Home-Desktop systemd[1]: sddm.service: Start request 
repeated too quickly.
Jun 10 17:08:06 Home-Desktop systemd[1]: Failed to start Simple Desktop 
Display Manager.

I have also noticed that using dpkg-reconfigure to specify the default 
display manager does nothing, the system tries to start sddm at boot 
time regardless of what is specified here as the default.

The only way I have been able to get the system to boot into lightdm as 
the display manager is to uninstall sddm.

The other thing that is of a concern to me that is slightly off-topic to 
this thread, is the timestamp that is on the systemctl output above. 
That timestamp is actually 10 hours ahead of local time, which indicates 
that Kubuntu assumes the bios time is set to GMT when in reality is 
isn't, and I don't know where to change that.

regards,
Steve

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