Intel Gets Back To Years-Long Journey Upstreaming PECI

Intel open-source engineers are back around with a new take on introducing a PECI subsystem for the Linux kernel to ultimately make their Xeon servers more attractive and friendly for OpenBMC usage.

PECI is the Platform Environment Control Interface and is for communication between Intel Xeon processors and BMCs / management controllers. The patches being worked on by Intel would bring-up a PECI subsystem within the kernel for managing this communication interface and provide various Intel drivers for PECI devices. The focus of this mainline support is to enhance the support for OpenBMC on Intel servers for that open-source BMC software stack that is Linux-based and in turn would benefit from mainline PECI support.

Intel engineers have been working on PECI patches for Linux for years but so far haven't gained enough traction/attention for getting it over the finish line. The last time there was a major PECI patch series prior to today was back in late 2019.

The 14 patches sent out today wire up the PECI subsystem and provide drivers for CPU package temperature and DIMM memory temperature reporting via this communication interface so it can be consumed by daemons running on the baseboard management controller such as for displaying on BMC web interfaces. PECI works with Intel Xeon CPUs (Xeon Scalable as well as Xeon E5/E7 v3/v4 CPUs) and ASpeed AST2400/AST2500/AST2600 SoCs. Again, the focus of this PECI work is for the likes of OpenBMC.

More details on this new PECI subsystem attempt for the Linux kernel in 2021 can be found via this patch series.