https://bugs.freedesktop.org/show_bug.cgi?id=90263
--- Comment #12 from Alex Deucher alexdeucher@gmail.com --- (In reply to Todd from comment #11)
I was expecting this problem to be solved through the miracle of "dynamic power management support" brought down from the mountain of Linux 4.
I had assumed that the GPU was running at full power all the time under the Linux Radeon driver, hence the loud fans. When booted to Windows 7, the card is quiet.
Is fan speed control a different issue? I'm losing track of what this issue is a symptom of and where to correctly report the bug.
Power management support has been available and enabled by default for your card for a while now (since 3.12 or so IIRC). The driver properly controls the clocks and voltages on your card. The fan control is somewhat independent. For most cards of this generation, the vbios sets up the fan profile to scale the fan based on GPU temperature and the driver just uses that. You happen to have a card with a limited vbios fan profile that requires the driver to set up smc fan control.