ryzenadj-rs

Rust bindings and a wrapper for the bundled RyzenAdj C library:

• ryzenadj-sys builds the C library and exposes its raw FFI.
• ryzenadj owns the handle, converts errors, and provides typed controls and borrowed access to the PM Table cache.

Build and run the reading example

The default build requires Rust, the RyzenAdj submodule, and these native tools:

Other architectures and Windows GNU targets are not supported by the build script. See the Windows limitation before running on Windows.

From the workspace root:

git submodule update --init
cargo build -p ryzenadj --example inspect

cargo run -p ryzenadj --example inspect

# or use root at Linux
cargo build -p ryzenadj --example inspect
sudo ./target/debug/examples/inspect

The inspect example prints CPU information and PM Table readings, explicitly refreshes once, and reads STAPM again. It calls query and refresh APIs only. PM Table refresh may send SMU commands to request a table transfer. Errors propagate from main, producing a nonzero exit status.

Handle and PM Table lifetime

The ryzenadj safe wrapper permits one live RyzenAdj handle at a time. RyzenAdj::new() returns Error::AlreadyInUse while another handle exists. Dropping the handle calls C cleanup and releases the wrapper's instance guard. This restriction is local to the process and does not cover direct calls to ryzenadj-sys.

new() creates the handle. power_table() refreshes the C cache, initializing it on demand, and returns a PowerTable that exclusively borrows the handle. Reading methods use that cache; call refresh() to update it explicitly. Setters do not refresh the cache automatically. End the table borrow before using the handle for another operation, as demonstrated by the example's inner scope.

values() returns a borrowed slice of raw cached floats. While that slice is still being used, Rust prevents refreshing the table. Structured readings such as PowerLimitReading are owned copies and can be kept after refreshing or releasing the table borrow.

Values, units, and core indices

Structured readings turn each NaN field into None independently. The raw slice from values() preserves NaNs.

PowerTable::core(index) takes a PM Table slot index. Per-core controls instead take types::CoreAddress, containing firmware CCD/CCX/core indices. Neither API translates OS logical CPU numbers. CoreAddress::new checks the encoding width, not whether a core exists. PM Table getters also inherit C's incomplete core count checks, documented on PowerTable::core.

Windows limitation

The upstream C Windows backend can dereference an uninitialized PM table mapping when cleaning up a handle. In particular, dropping a handle before accessing its PM table, or some initialization failures, may crash.

STAPM time limitation

For several CPU families, the upstream C set_stapm_time() switch falls through after its first SMU request and sends a second request. The returned status may describe that second request. RyzenAdj::set_stapm_time() preserves this upstream behavior until it is fixed in C.