Both fglrx and radeon support dynamic power management so this does not likely have anything to do with power management. It looks like a plain old GPU hang. I'd suggest updating your mesa stack in the case of the open source driver.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/881526 Title: AMD graphics hardware hangs with an homogeneous coloured screen or blank screen, and with chirp coming from the graphics card To manage notifications about this bug go to: https://bugs.launchpad.net/mesa/+bug/881526/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs