You can manually select a power state and clock mode:
echo 3.0 > /sys/class/drm/card0/device/power_state
will select power state 3, clock mode 0.
echo 3.0 > /sys/class/drm/card0/device/power_state
will select power state 3, clock mode 0.
2.6.34-0.38.rc5.git0.fc14.i686 #1 SMP
[drm] radeon: power management initialized
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