fglrx and sddm

[imrazor]

I'm trying to get Kubuntu 15.04 working satisfactorily on my laptop, and am running into numerous issues with graphics drivers. For whatever reason, the OpenGL performance of the open source driver is no better than software rendering. Plus running a game with the open source driver causes reboots and crashes of the X desktop. Due to these issues, I had to go with fglrx-updates. This works better with games, but I'm having issues with the desktop, primarily I think with sddm.

The first symptom is that sddm-greeter crashes right after login. The desktop loads, but I'm welcomed with a crash report for sddm-greeter. The next obvious symptom is a krunner and/or kdeinit5 crash during reboot. Thirdly, if the session locks, it is impossible to unlock it. If you enter the correct password on the lock screen, the screen goes blank for a moment, then goes right back to the lock screen. And finally, the laptop will not resume from sleep. The backlight stays on, and the computer will not respond to any keyboard/mouse interaction.

Any suggestions for dealing with these issues? I can disable the lock screen entirely, but that's not the most secure way to run a PC. It occurred to me to replace sddm with a different display manager, but I'm not sure if that's possible with KDE 5/Plasma. If so, how would I go about it? Another possibility would be to revert to Kubuntu 14.10, but I really like the new desktop environment. However, I'm not sure that even that would prevent the fglrx crashes I'm seeing.

My laptop is a Dell Precision M6600 with an AMD Firepro M6100 GPU.

Also as an aside, these problems completely go away if I use the open source driver. The issue with them is OpenGL performance and game crashes. I suppose I could change them on the fly, but that strikes me as cumbersome and potentially dangerous.

[OneLine]

Problem solving - what I would do

For whatever reason, the OpenGL performance of the open source driver is no better than software rendering.

I would:

- check the cpu load
- check the /var/log/Xorg.0.log
- check the .xsession-errors
- check the other logs: https://help.ubuntu.com/community/LinuxLogFiles

running a game with the open source driver causes reboots and crashes of the X desktop.

I would:

- check the /var/crash/
- check the .xsession-errors

I had to go with fglrx-updates. This works better with games, but I'm having issues with the desktop, primarily I think with sddm.

The first symptom is that sddm-greeter crashes right after login...

I would:

- check the /var/log/Xorg.0.log
- check the /var/crash/

[OneLine]

'display' manager

It occurred to me to replace sddm with a different display manager, but I'm not sure if that's possible with KDE 5/Plasma. If so, how would I go about it?

The display manager or login manger is an optional thing.

You could use your system without a display/login manager or change the dm.

More:

- https://en.wikipedia.org/wiki/X_disp...(program_type)



- https://en.wikipedia.org/wiki/Xinit

A Ubuntu how to : http://www.webupd8.org/2011/07/how-t...ightdm-or.html


The SDDM is the Kubuntu default dm for the Vivid.
The metapackage kubuntu-desktop ( http://packages.ubuntu.com/vivid/kubuntu-desktop ) is depending the package: sddm-theme-breeze ( http://packages.ubuntu.com/vivid/sddm-theme-breeze ). The sddm-theme-breeze is only recommending the package: sddm ( http://packages.ubuntu.com/vivid/sddm ). That is: the sddm can be removed without breaking the kubuntu-desktop.


An example

Testing one dm.

A Ubuntu package:

:~$ apt-cache show nodm
Package: nodm
Priority: extra
Section: universe/misc

Description: automatic display manager
This package prepares the system to automatically start an X session at
system boot. It is meant for devices like smartphones, but can be used on
a regular computer as well, if the security implications are acceptable.

The same thing could be achieved with the sddm: https://wiki.archlinux.org/index.php/SDDM#Autologin
The LightDM/KDM has a graphical setting for this.


1) Installing the nodm

sudo apt-get install nodm

2) Configuring the nodm

sudo dpkg-reconfigure nodm

3) Optional - there could be more than one dm - removing the sddm

sudo apt-get purge sddm

4) Reboot - working without problems - at here.

[imrazor]

Well, that was odd. I figured I'd take the easy way out and try a different display manager. I tried lightdm first and got an odd result. After installing, I ran dpkg-reconfigure lightdm and selected lightdm as the default display manager. However, after reboot sddm still tried to load, along with lightdm. The sddm login would display for a few seconds, then it would alternate to lightdm, then back to sddm. Finally it settled on the lightdm login screen. However, when trying to login I got a message "Failed to start session." So I rebooted to the reboot/recovery console and successfully reverted back to sddm. Then I tried installing gdm, followed by dpkg-reconfigure. After reboot, I got a blank black screen. So it looks like I get to try and troubleshoot sddm and fglrx.

I considered nodm, but I was concerned about the "security implications" mentioned in your description.

I get a crash log from sddm-greeter right after I login, but it's different from the log in /var/crash. What's the difference? The crash log I get after login says it's "not useful", but does mention libGL.so.1 several times. Is it really useless? Keep in mind this is with fglrx installed.

BTW, thanks for taking the time to write such detailed troubleshooting steps. However, the crash logs you reference are largely incomprehensible to me. The Xorg log is easier to understand. I see errors there about not being able to find a file called fglrx_dri.so, XMM failing to initialize, "cannot read int vect" errors, and failing to open /dev/dri/card0. In spite of the DRI errors, hardware acceleration is occurring, at least in games.

[imrazor]

Problem solved, or maybe worked around would be a better way of putting it.

sudo apt-get install ubuntu-desktop
sudo dpkg-reconfigure lightdm
sudo apt-get purge sddm

Not quite that simple, but that's the gist of it. Only downside - now I'm stuck with Unity. No more crashes, though. Too bad I couldn't get lightdm to work with KDE/Plasma.