Comment 8 for bug 700646

According to the status matrix at http://nouveau.freedesktop.org/wiki/FeatureMatrix the NVC0 support in the Nouveau driver has improved since your post on 20th April 2011. Further to note 9 on that page, the upcoming Linux 3.1 kernel will be able to generate the necessary firmware automatically - a PPA of the first release candidate of this kernel (3.1-rc1) should soon be available at http://kernel.ubuntu.com/~kernel-ppa/mainline/
See http://www.phoronix.com/scan.php?page=news_item&px=OTcxMg for further details.

The proprietary NVIDIA driver has also improved and may be worth another try - the latest stable release is 275.19, available from http://www.nvidia.com/object/linux-display-amd64-275.19-driver.html
It fixes several bugs.

More information about the bumblebee (prime-ng 2.0) for Optimus that Rocko described above can be found at http://www.phoronix.com/scan.php?page=news_item&px=OTQxNg
An alternative approach for some Optimus laptops was also added to the Linux 3.0 kernel which will be used by the upcoming Ubuntu 11.10 "Oneiric Ocelot" - see http://www.phoronix.com/scan.php?page=news_item&px=OTQzMA for further details (this article refers to the 2.6.40 kernel but it was decided to rename this kernel to 3.0).

Ubuntu 11.10 "Oneiric Ocelot" alpha 3 will be released on August 4th 2011 if you want to test it before it's final release on October 13th 2011 - see https://wiki.ubuntu.com/OneiricReleaseSchedule