Linux 6.11-rc2 To Recognize More AMD Zen 5 CPUs

Ahead of the Linux 6.11-rc2 kernel due for release later today there is the weekly "x86/urgent" material to merge.

The x86/urgent churn this week includes a deadlock fix in the aperf/mperf driver and some other fixes. Arguably most notable is adding some missing AMD Zen 5 CPU model numbers.

The AMD Linux code has been treating Zen 5 as Family 1Ah processors with model IDs between 0x00 to 0x2f, 0x40 to 0x4f, and 0x70 to 0x7f. But it turns out that it should be 0x60 to 0x7f as recognized Zen 5 models... That 0x60 to 0x6F model range were not covered by the current Linux kernel (models 96 to 111).

Current AMD Ryzen AI 300 "Strix Point" processors are Family 26 Model 36 and the upcoming Ryzen 9000 "Granite Ridge" are Family 26 Model 68. So the kernel's shortcoming of not recognizing the entire range of Zen 5 isn't immediately pressing but presumably some additional parts will eventually be released in that newly expanded range.

So far Family 26 (1Ah) is just used by Zen 5 processors and in some areas like the LLVM Clang compiler is treating all Family 26 processors with models 128 or less as Zen 5. If traditions hold, Family 26 may end up being shared with Zen 6 too before moving onto a different family ID.

Anyhow, today's x86/urgent pull request for merging before the Linux 6.11-rc2 release tonight has that expanded range of AMD Zen 5 model numbers.