PowerCap/RAPL Code To Support Icelake Desktop / X / Xeon D With Linux 5.3

While as of Linux 5.2 the support for Intel's Icelake CPUs appear production ready with all of the bits in place from new IDs to the much enhanced "Gen 11" graphics, there are a few stragglers of items to land with the upcoming Linux 5.3 merge window though could be back-ported to current series. Fortunately, we haven't found anything major to be missing.

One of the latest bits of Icelake Linux support is handling of these next-generation processors within the PowerCap / RAPL (Running Average Power Limit) driver code. In particular, the desktop/workstation Icelake parts. This is the code for reading the estimated CPU package power consumption based on hardware performance counters and the ability to artificially limit the power draw of the processor via software.

Just new PCI IDs were needed and they have now been staged in the "-next" tree of the Linux kernel's power management code. This adds the Icelake PCI IDs for the desktop parts, Icelake-X, and Icelake Xeon Ds. Icelake mobile IDs were already in place. But with Icelake desktop/X-Series/workstation parts likely not coming anytime soon, this support hitting for Linux 5.3 should be sufficient.

Linux 5.3 should be picked up by the likes of Ubuntu 19.10 and Fedora 31 so overall for the autumn 2019 Linux distribution updates the Icelake support should be in good standing out-of-the-box for the upcoming mobile platforms and the higher-tier Icelake parts down the road.