The problem with testing this theory is that "radeon.audio=0" doesn't completly disable the audio. I was able to fix the crash, but still when I boot with audio=0 i get the same behaviour. Now there are two posibilities, either audio frames are not related or the guilty frame gets sent even with audio=0. In order to rule out option 2 someone who understands the code should make sure that audio=0 actualy disables everything related to audio.