I've gone through the above linked bug report regarding this issue in preparation for the imminent arrival of my PanP5. I have a thought regarding this problem until Karmic goes gold.
According to the bug report, the problem is also fixed in the 2.6.30 kernel. I've been using that kernel as a drop-in replacement on my current system (32 bit) since its RC days without an issue due to the Intel Video problems in Jaunty. It is a pretty painless install - here is the code for getting and installing the 64 bit version:
On the down side, this kernel will break AppArmor, so people who need AppArmor won't be able to use it. I don't know if there are other problems that I didn't think of. As I said, I've been using it on a 32 bit Dell system, so I don't know what unintended consequences the 64 bit 2.6.30 kernel might have on a System76 computer.
$ wget -c http://kernel.ubuntu.com/~kernel-ppa/mainline/v220.127.116.11/linux-headers-2.6.30-02063005-generic_2.6.30-02063005_amd64.deb http://kernel.ubuntu.com/~kernel-ppa/mainline/v18.104.22.168/linux-headers-2.6.30-02063005_2.6.30-02063005_all.deb http://kernel.ubuntu.com/~kernel-ppa/mainline/v22.214.171.124/linux-image-2.6.30-02063005-generic_2.6.30-02063005_amd64.deb
$ sudo dpkg -i linux-headers-2.6.30-02063005-generic_2.6.30-02063005_amd64.deb linux-headers-2.6.30-02063005_2.6.30-02063005_all.deb linux-image-2.6.30-02063005-generic_2.6.30-02063005_amd64.deb