Then you can do this to make the ARM run at 400MHz while the DSP task is running at 133MHz: "echo 0 > /sys/power/op_dsp" To go back to the default (ARM at 330MHz while DSP running at 220MHz) do this: "echo 1 > /sys/power/op_dsp"

> Also I wonder what happens when I set DSP_CLK_KHZ in OP_0 state to
> 266000, can I damage the hardware or will the DSP just crash (leaving
> rest of the system relatively OK)?

Depending on many conditions, it might or might not work, however as
long as you don't crank up the voltage, there is no risk of damaging the
silicon.

HOWEVER (!) corruption in the DSP execution path might lead to
unpredictable results, including bricking the unit (to that point that
cold flashing is required). Overclocking the DSP only should not so
easily cause damage but it's not really a black and white situation.
Also you might have to play with the synchronizer.