Running Linux on an Nvidia RTX Spark laptop: it installs, but the GPU is locked at 780 MHz

Linux can be installed on Nvidia RTX Spark laptops such as the MSI Prestige, and GPU acceleration can be enabled through Nvidia's open-source kernel driver, but when plugged in the GPU clock is locked at about 780 MHz, whereas under Windows it can reach about 2.2 GHz. In GPT-OSS-120B tests, Windows measured 65.4 tokens/s, WSL 65.1 tokens/s, and DGX Spark 61 tokens/s, while native Linux managed only 13.9 tokens/s. The root cause is that the Nvidia Platform Controllers and Framework, which is available only on Windows, handles CPU and GPU power scheduling, and its encrypted power tables cannot be read by Linux.