AMD Readies Official Ryzen Overclocking Driver for Linux

AMD is reportedly working on official Ryzen overclocking controls for Linux. Per Phoronix, AMD engineer Shyam Sundar S K has posted a three-patch series for a new driver called AOD, short for AMD Overclocking Driver, to the platform-driver-x86 mailing list. It is a WMI driver that talks to the same firmware interface Ryzen Master uses on Windows, with all of its controls exposed through sysfs. For now, that covers PPT, TDC, and EDC limits along with their supported ranges, a platform-level SMT toggle, and a read-only memory clock readout. Notably, Ryzen Master itself isn't coming to Linux with this. AMD seems to be following the same approach it took with its amdgpu graphics driver, handling the kernel side and leaving the GUI to third-party tools such as CoreCtrl and to desktop environments.

There are a few catches, however. Power limit changes are stored in firmware and only kick in after a reboot. AMD's existing HSMP interface works the other way around, applying limits instantly but losing them on restart. The PPT, TDC, and EDC attributes are also write-only, since the firmware doesn't report the currently active values. The SMT switch, meanwhile, behaves more like a BIOS option than the kernel's nosmt boot parameter. Apparently, the firmware supports many more commands than the initial patches wire up, so more controls could arrive later. The patches are still under review, and there is no word yet on which kernel release will pick them up, so a proper Linux app for this is probably still a while away.