Comment 167 for bug 585765

I had been seeing this problem on a new ThinkPad W510 running 10.04.

The symptom I was seeing was that the screen would lock up at random times over the course of the day, sometimes after several hours, other times after just a few minutes. I saw lockups after leaving the machine running while I was away from it, but more frequently while actively using the machine. Typically, lockups would happen when I did something actively, such as clicking on a link in Firefox or hitting the return key while in gnome-terminal. In most cases, the cursor arrow could be moved about the screen, but the system would not respond to any input from keyboard or mouse.

After reading this thread, I tried to ssh into my machine while it was locked up. I never found a case when this failed to work. In every case, top showed Xorg running near 100% CPU utilization. I tried to kill Xorg by sending it a signal, but a new Xorg process (with a new PID) would be created, executing at 100% CPU utilization, and still unresponsive to keyboard and mouse.

A coworker with a similar setup to mine said he wasn't seeing any problems like this but that he had had similar problems when he first installed Ubuntu 10.04. After comparing notes, it came to light that he had switched from the free graphics driver that Ubuntu installs by default to the proprietary non-free NVidea driver.

I switched to the non-free driver last week and have not seen the problem even once since switching.

I am able to run pulse audio, and I'm even able to turn on desktop effects that were sure to kill my old T40.