X freeze on Notebook - solved?

This bug report at the Ubuntu Launchpad ([i965] X freezes starting on April 3rd) seems to describe the problem I've been having over the last few weeks with my notebook running Ubuntu Jaunty 9.04.  In essence, at some point, usually 2-24 hours after the last boot, the system will freeze up - the display is immobile (though the mouse pointer moves) and there appears to be no input from keyboard or trackpad buttons.  Other than that, the system is running happily, as far as I can tell from logging in remotely.

In a previous blog post (Firefox, Opera and Ubuntu 9.04 Jaunty), I'd thought that the problem lay with Firefos, but that turned out not to be the case.  From the bug report, it would seem to be related to the Intel graphics card the current theory being:

A 3D memory buffer accumulates data until something gets in there incorrectly and leads to a freeze. This can happen either slowly over a long period of light use, or fairly soon if using the system heavily. It is not simply a matter of filling the memory up, so the trigger often seems to be random, but usually follows some sort of graphics transition (such as the 3D effect from alt-tab, or closing a firefox window).

It is fairly certain that there are multiple freeze bugs present in X.org with the -intel driver. This causes significant confusion when people having different bugs think they might have the same one, and find the symptoms and workarounds don't match. It is also suspected that the same root bug may have multiple different ways of triggering it.

Increasing the Virtual settings seems to either eliminate or greatly reduce the frequency of these freezes. Presumably this allocates larger memory buffers so the chances of something hitting a wrong thing are greatly lessened. However, none of this is well understood.

I imagine that this is why the freezes usually occur while I'm using Firefox, as there is considerable scrolling involved in web page use.

In any event, I tried making changes to xorg.conf, I tried downgrading to these packages:

libglu1-mesa_7.3-1ubuntu4_i386.deb
libgl1-mesa-dri_7.3-1ubuntu4_i386.deb
libgl1-mesa-glx_7.3-1ubuntu4_i386.deb
mesa-utils_7.3-1ubuntu4_i386.deb

That didn't seem to help, so I tried upgrading those packages to version 7.5.  That didn't help.  I've now upgraded xserver-xorg-video-intel to version 2.8, and the notebook has been running now for 17 and a half hours without a freeze.  Perhaps the problems have been sorted...

Onwards and upwards!