This is a bug transitioned from launchpad: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/384275

I encounter a reproducable hard system lock when I run glxgears and then start a movie in gmplayer.

This only appears when using KDE4 and enable desktop effects (it doesn't matter which of them are enabled).

The steps to reproduce:

1. Log into KDE4
2. open a konsole and run glxgears
3. open a movie in gmplayer (mplayer/kmplayer/smplayer/dragon NOT affected)
4. wait a few seconds for the crash

The result is either:
1. primary display goes off
2. secondary display freezes
3. keyboard unresponsive
4. even SSH doesn't work any longer

This issue cannot be raised within XFCE or within KDE4 without using effects with the same applications.

No messages are given anywhere when it crashes. It just locks at some point.

System hardware:
- AMD Athlon 64 X2 4400+
- ATI Radeon X1950 XTX

Software environment:
- Kubuntu 9.04 Jaunty Jackalope
- KDE 4.2.2 (proposed)
- xserver-xorg-video-radeon driver (version doesn't matter, tested with 6.12.1 and latest git master)

In addition to the result above I also successfully raised a similar issue by just running gmplayer and while playing a movie moving the controller window around the screen. After some seconds either both displays go off and I have a hardlock again or the screen just freezes and nothing happens (mouse pointer still moving = HW-cursor, keyboard dead). But in the second case I can still log in via SSH and I see in "top" that the system just does nothing.

As I tested with a second X1950 XTX from a different vendor I can confirm that this is not a hardware failure.

Ancoron