I have somewhat similar hardware and have problems with crackling audio on Ubuntu Lucid when using radeon KMS. If I disable KMS the crackling goes away completely. Try booting with "radeon.modeset=0" parameter and see if that helps.
I have somewhat similar hardware and have problems with crackling audio on Ubuntu Lucid when using radeon KMS. If I disable KMS the crackling goes away completely. Try booting with "radeon.modeset=0" parameter and see if that helps.