amdgpu: Manual Card Configuration Change

Hello all,

Regarding amdgpu, I've been using some Radeon 5700XTs for compute work with kernels through 5.8.14. I recently tried kernel 5.9.0, and found that the following is no longer allowed:

echo "m 1 200" | sudo tee /sys/class/drm/card0/device/pp_od_clk_voltage

Is this an expected change? If so, where should I look for documentation regarding how to manually configure these cards with this kernel. Note, I've had this working with 5.8 kernels for months.

Thanks

Josh