AMD Posts New Linux Patches Enabling Dynamic Boost Control
Mario Limonciello of AMD's Linux client team who has been working on many new AMD Linux features and fixes the past two years sent out today's patches for enabling Dynamic Boost Control under Linux via their AMD Cryptographic CoProcessor (CCP) / Platform Security Processor driver.
Mario explained in today's patches:
"Dynamic boost control is a feature of some SoCs that allows an authenticated entity to send commands to the security processor to control certain SOC characteristics with the intention to improve performance.
This is implemented via a mechanism that a userspace application would authenticate using a nonce and key exchange over an IOCTL interface.
After authentication is complete an application can exchange signed messages with the security processor and both ends can validate the data transmitted.
This series includes a test suite that can be run on real hardware to ensure that the communication works as expected. This can also be used for an application to model the communication path.
Two sysfs files are introduced for reading the PSP bootloader version as well as TEE version which can be useful data points for debugging communication problems."
Dynamic Boost Control with capable Ryzen SoCs can read and set various frequency/power limits. However, only software authenticated with the AMD PSP is able to read/set these limits. Among the AMD Dynamic Boost Control parameters are around the power cap, frequency capping, and graphics power mode. There are more query parameters too for items like SoC power minimum, frequency max inimum, and current temperature -- some of which data is already available through alternative interfaces on Linux.
Once this AMD Dynamic Boost Control (DBC) support lands, it will be exposed to (authenticated) userspace via a new /dev/dbc device. See the patch series for more information on the AMD Dynamic Boost Control support for Linux.
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