In addition to my desktop computer that has a Radeon 3650 video card in it, I have an Lenovo T400 laptop that has and Intel and an ATI video card in it. I have been using the Intel card primarily as it gives good battery life and the fan in the machine does not run much. With the Linux 2.6.35 kernel being out that supports Radeon power management I thought I would give it a try.
Fedora 13, my OS of choice, currently only has kernel 2.6.34 available. So I went to koji and grabbed the latest kernel source package. I made sure I had the dependencies for building the kernel installed, by running yum-builddep kernel. I then took the kernel source package I had and rebuilt it using rpmbuild --rebuild [kernel src rpm]. This process took awhile, but eventually I got a set of kernel packages. I then changed to the ~/rpmbuild/RPMS/x86_64 directory and ran yum --nogpgcheck upgrade kernel*. Once that was installed I rebooted into the new kernel. I then followed the wiki to enable dynpm. I actually placed the options in my /etc/rc.local file so they were applied on every reboot. The system seemed to work ok, but had a little flashing every now and then do the video clocks changing, so I upgraded the xorg-x11-drv-ati rpm using the same process as I did for the kernel and rebooted again. So far the ATI card seems to be working fine, I still have a few flashes every now and then and the battery life is not as good as when using the Intel card. But the 3d performance is much better.
I have not upgraded Mesa on this machine yet, so it is still using Mesa 7.8.