AMD Zen 2 Temperature Monitoring Changes Sent In For Linux 4.21

Written by Michael Larabel in AMD on 25 December 2018 at 07:35 AM EST. 1 Comment
When AMD Zen CPUs originally rolled out, the ability to monitor the CPU core temperatures under Linux didn't roll out until months later. Fortunately, for Zen 2 the AMD Linux CPU temperature driver looks like it will be ready in time.

Back in November when patches first emerged I commented on AMD already working on temperature driver support for Zen 2, or AMD Family 17 Model 30h and newer. Special changes are needed with the new processors having multiple roots per Data Fabric / SMN interface.

That code is now sent in as x86/amd-nb changes for the Linux 4.21 kernel.
Updates the data fabric/system management network code needed to get k10temp working for M30h. Since there are now processors which have multiple roots per DF/SMN interface, there needs to some logic which skips N-1 root complexes per DF/SMN interface. This is because the root complexes per interface are redundant (as far as DF/SMN goes). These changes shouldn't effect past processors and, for F17h M0Xh, the mappings stay the same.

This temperature monitoring support is on top of other "Zen 2" Linux patches we've begun seeing in Q4'2018 for ensuring these next-gen AMD processors will be fully supported by Linux by the time they officially launch in 2019.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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