Linux Will Finally Report Temperatures For Certain AMD Excavator CPUs

Besides the Linux "k10temp" AMD CPU temperature reporting driver recently seeing support for Threadripper 2 temperature monitoring, much older Excavator (Bulldozer 4th Gen) processors will now see working CPU temperature reporting for select models.

While AMD Excavator CPUs came out in 2015, particularly in the APU form like Carrizo, not all of these models have had working CPU temperature reporting even with the latest Linux kernel code. Excavator CPUs in the Family 15h (Bulldozer) have a CPUID model between 60h and 6Fh and newer revisions between 70h and 7Fh. But the k10temp Linux driver up to now has just been checking for 60h and 70h, not any of the other model numbers.

While 60h/70h seems to cover most of the Excavator parts, there have been some APUs like the A10-9620P that have a Model 65h number and thus haven't been supported by k10temp due to failing this simple check.

But now there's a patch pending to correct the behavior of the k10temp driver so it properly checks for the entire range of Excavator models. Hopefully this will work its way into Linux 4.19 and for back-porting as a "fix" for those still relying upon this last generation of Bulldozer processors.

It seems temperature reporting under Linux hasn't been the highest priority for AMD with the missing Threadripper support for recent CPUs but also this Excavator incident and just with Linux 4.18 came temperature support for Stoney and Bristol Ridge, more older AMD APUs. These patches as well haven't been coming from AMD but rather Guenter Roeck and other hwmon subsystem developers.