Method to Lock the NPU Frequency on Lunar Lake (LNL)

Hi, I'm benchmarking Qwen2-0.5B inference using GenAI on an LNL platform and observing up to 15% token generation latency variation between different runs, likely due to NPU frequency scaling (DVFS). For reproducible performance results, I need a way to lock the NPU to a fixed frequency.

Standard DVFS controls seem to act only as hints. I found a kernel patch for getting DPU frequency ([link](https://lore.kernel.org/dri-devel/8dbc2f5a-cec4-43c7-a592-285d9b85c938@linux.intel.com/)), but not for setting the NPU frequency.

Is there a recommended way to lock the frequency? As a potential workaround, would setting the `pll_min_ratio` and `pll_max_ratio` kernel parameters to the same be a viable approach?

Things I have done to minimize the variation:
`sudo powerprofilesctl set performance`
`sudo sh -c "echo 1 > /sys/kernel/debug/accel/0000:00:0b.0/dvfs_mode"`