Here is a status of this problem on my laptop with the latest quantal updates. I have attached powertop's HTML output. What I find confusing is that audio devices are listed both at 100% and 0% usage in the same powertop run:
100.0% PCI Device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller
100.0% PCI Device: Advanced Micro Devices [AMD] nee ATI RV635 HDMI Audio [Radeon HD 3600 Series]
0.0% Audio codec hwC0D0: Analog Devices
0.0% Audio codec hwC0D1: LSI
Can somebody explain this ?