Happy to report Alexander's patch worked for me as well.
Ubuntu 14
Kernel 3.13.0-24-generic x86_64
Radeon HD 5450 (open 'radeon' driver)
Connected via HDMI to an A/V receiver (connected to TV)
Power-cycling the receiver caused the issue before the patch
Happy to report Alexander's patch worked for me as well.
Ubuntu 14
Kernel 3.13.0-24-generic x86_64
Radeon HD 5450 (open 'radeon' driver)
Connected via HDMI to an A/V receiver (connected to TV)
Power-cycling the receiver caused the issue before the patch