The Intel_Idle Linux Driver Prepares For Grand Ridge SoCs

While some at Intel were busy launching the 5th Gen Xeon Scalable "Emerald Rapids", other Linux engineers at the company were pushing ahead on their new hardware enablement quest for future platforms. Sent out on the same day as Emerald Rapids being announced were continued patches for enabling Grand Ridge.

Grand Ridge is an upcoming Intel Atom SoC that has been rumored to be a 7nm ~24 core processor. Intel's been working on the Grand Ridge Linux enablement for a while as well as bringing up the compiler toolchain support in GCC and LLVM/Clang and the like. The latest is enabling Grand Ridge for the Intel_Idle driver. This is the the Intel CPU idle time management driver for dealing with the processor's core and package idle states.

With the new patches for the intel_idle Linux driver it sums up the Grand Ridge SoC changes as:

"Add Intel Grand Ridge SoC C-states, which are C1, C1E, and C6S.

The Grand Ridge SoC is built with modules, each module includes 4 cores (Crestmont microarchitecture). There is one L2 cache per module, shared between the 4 cores.

There is no core C6 state, but there is C6S state, which has module scope: when all 4 cores request C6S, the entire module (4 cores + L2 cache) enters the low power state."

This Intel_Idle support for the long-talked-about Grand Ridge in turn could be mainlined for the Linux v6.8 or otherwise v6.9 cycles coming up in 2024.