I've been using Ubuntu on my dv8225nr and the support is just fine. Everything works out of the box except you need to install fglrx drivers if you want 3d acceleration. Also the wireless card firmware needs to be installed. Here's
a quick info post I made a while back that worked on Edgy, the previous version of Ubuntu. I had some issues getting the fglrx driver working in Feisty, the latest version, so instead if following the guide linked there use this one
and follow Method 1.
Some people will recommend using ndiswrapper for the bcm4318 wireless card but I've had nothing but problems with that method and what works WAY better is the what I posted in the previous about edgy in this post
If you'd like to try it, this should get you up and running with Ubuntu Feisty like I did. When I first installed Ubuntu I chose to write over the recovery partition because it was wasting a lot of space. It was nice of HP to add a partition that fits linux so nicely
Hope this info has been helpful...