[SOLVED] KDM systemd service has got wrong dependencies

DoDoENT · 2014-03-20 00:37:32

KDM systemd service has got wrong dependencies...

... at least I think so.

Here is the problem I am facing:

if I enable KDM systemd service to start on boot, my system boots and leaves me with blank screen. I am even unable to switch to tty consoles. However, it appears that login proceeds normally because I can hear my KDE login sound (I've configured KDM to perform automatic login). On the other hand, if I disable the KDM service and manually start it after logging in into tty, it works normally. Is there a way to delay the startup of KDM until boot finishes? Currently /usr/libsystemd/system/kdm.service has got following contents:

[Unit]
Description=K Display Manager
After=systemd-user-sessions.service

[Service]
ExecStart=/usr/bin/kdm -nodaemon

[Install]
Alias=display-manager.service

I believe this means that it should be started after systemd-user-sessions.service. Apparently in my case this is too early - I end up with blank monitor. I need KDM to wait even more before starting. What is the last unit that systemd starts? How can I check that on my system? Is there a way to tell unit to wait 500 ms before executing a line from ExecStart? I don't mind waiting a second or two more for KDM startup if it will start for sure - it would still be faster than logging in into tty and manually starting the KDM service.

Last edited by DoDoENT (2014-03-20 10:32:50)

DoDoENT · 2014-03-20 00:59:04

I've also tried modifying the /usr/lib/systemd/system/kdm.service by adding WantedBy=multi-user.target but without any luck. It didn't help.

[Unit]
Description=K Display Manager
After=systemd-user-sessions.service

[Service]
ExecStart=/usr/bin/kdm -nodaemon

[Install]
Alias=display-manager.service
WantedBy=multi-user.target

The screen just keeps beeing off - like driver was not initialized properly. Closing the laptop lid and opening it again does not help - it just turns on the screen backlight. The only solution to start the X server is by logging in to tty and manually start the KDM.

Does anyone have any better idea?

Padfoot · 2014-03-20 08:52:27

Try the following:

[Unit]
Description=K Display Manager
Conflicts=getty@tty1.service
After=systemd-user-sessions.service getty@tty1.service

[Service]
ExecStart=/usr/bin/kdm -nodaemon
Restart=always
IgnoreSIGPIPE=no
StandardOutput=syslog

[Install]
Alias=display-manager.service

DoDoENT · 2014-03-20 09:20:32

Padfoot wrote:

Try the following:

[Unit]
Description=K Display Manager
Conflicts=getty@tty1.service
After=systemd-user-sessions.service getty@tty1.service

[Service]
ExecStart=/usr/bin/kdm -nodaemon
Restart=always
IgnoreSIGPIPE=no
StandardOutput=syslog

[Install]
Alias=display-manager.service

Thank you for your suggestion. Unfortunately it does not work. Out of 4 boots, 3 time I ended up with blank screen. Interestingly, in the last boot I was able to switch to tty1 just after screen went blank and managed to log in to tty. I've restarted the kdm.service then manually in hope the image will be restored, but it wasn't. The restart of kdm then made the screen totally blank and I was unable to switch to tty anymore.

Is it possible that radeon module in kernel has some slow initialization procedure and if X requires its services before it is properly initialized it ends up with blank screen?

Raynman · 2014-03-20 10:21:05

DoDoENT wrote:

Is it possible that radeon module in kernel has some slow initialization procedure and if X requires its services before it is properly initialized it ends up with blank screen?

I don't know, but if you're not using early KMS start already, try that.

DoDoENT · 2014-03-20 10:32:16

Raynman wrote:

DoDoENT wrote:
Is it possible that radeon module in kernel has some slow initialization procedure and if X requires its services before it is properly initialized it ends up with blank screen?
I don't know, but if you're not using early KMS start already, try that.

This not only solved my issue, but increased the boot speed. Thank you, thank you, thank you! You are the hero of the day!

Arch Linux

#1 2014-03-20 00:37:32

[SOLVED] KDM systemd service has got wrong dependencies

#2 2014-03-20 00:59:04

Re: [SOLVED] KDM systemd service has got wrong dependencies

#3 2014-03-20 08:52:27

Re: [SOLVED] KDM systemd service has got wrong dependencies

#4 2014-03-20 09:20:32

Re: [SOLVED] KDM systemd service has got wrong dependencies

#5 2014-03-20 10:21:05

Re: [SOLVED] KDM systemd service has got wrong dependencies

#6 2014-03-20 10:32:16

Re: [SOLVED] KDM systemd service has got wrong dependencies

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