Black screen after changing user

[hansdevr]

This weekend, I added the members of my family as users. No problem, as long as I log off and someone else logs in, but when I try to change user (from the K-menu) I just get a totally black screen. Mouse pointer is gone and everything stays black... I must reboot the system.

What can be wrong?

[lmilano]

Re: Black screen after changing user

Hi, it could be the combination of login manager and graphics driver. What are you using? I assume KDM. How about graphics?

[hansdevr]

Re: Black screen after changing user

It's an ATI Sapphire HD 3870 with 512 Mb, PCIe

[lmilano]

Re: Black screen after changing user

Are you using the open source or binary drivers? I am suing an ATI IGP with thje binary FGLRX and I can switch. But installing them in jaunty can be VERY tricky. I did have KDM issues with the nvidia drivers thought.

Things to try:
* disable desktop effects (if enabled) and try
* install GDM and try

In general though, I am not sure user switching is the best thing, I am afraid a user could lock the sound for the others, etc.

[hansdevr]

Re: Black screen after changing user

Are you using the open source or binary drivers? I am suing an ATI IGP with thje binary FGLRX and I can switch. But installing them in jaunty can be VERY tricky. I did have KDM issues with the nvidia drivers thought.

Things to try:
* disable desktop effects (if enabled) and try
* install GDM and try

In general though, I am not sure user switching is the best thing, I am afraid a user could lock the sound for the others, etc.

Err... what's GDM?

[lmilano]

Re: Black screen after changing user

Err, the same thing a google search shows at the top
http://en.wikipedia.org/wiki/GNOME_Display_Manager

[hansdevr]

Re: Black screen after changing user

I don't understand.. Why would I want to use the Gnome display manager when I run Kubuntu with KDE?

[lmilano]

Re: Black screen after changing user

You don't have to. But you may want or need to, it's up to you. For instance, there is an old (never fixed) bug in the NVIDIA binary driver, affecting some cards, that makes you have a system crash on logout using KDM. GDM works in those systems.

[hansdevr]

Re: Black screen after changing user

OK, thanks, I will check that out.