Upgrading to Lenny has its share of pros and cons. Among the problems I have encountered were 3D acceleration and sound problems.
You would find them here.
Both of the problems have been solved and this is my way of sharing the experience should somebody experience them again.
The first symptom that I encountered was the sound was muted. When I clicked on the Gnome Mixer (Volume Control) icon, it showed an error:
The volume control did not find any elements and/or devices to control. This means either that you don't have the right GStreamer plugins installed, or that you don't have a sound card configured.
You can remove the volume control from the panel by right-clicking the speaker icon on the panel and selecting "Remove From Panel" from the menu.
I solved this problem through Google Groups:
Get the firmware packageThanks to Gabor Burjan on this one.
and run ./configure && make && make install
After this you should have the following files present:
Then, run rmmod snd_maestro3 and modprobe snd_maestro3 again.