Too Busy For Words - the PaulWay Blog

I bought an AMD Ryzen processor and compatible motherboard as an upgrade for my home server. Seriously, this thing rocks! Four cores, eight threads, and still 65W of total power draw on the processor.

You need a fairly recent kernel to support the AMD Ryzen processor - the stock CentOS 7 kernels will intermittently and randomly lock up. One way of dealing with this is to install an updated kernel from EL Repo or similar, and that worked for me for a time. But at some point it dropped support for the Hauppauge NovaT USB DVB input I have for recording for MythTV, and I had to recompile the kernel. There are plenty of instructions out there for how to do that and it's relatively painless.

One thing that isn't currently included in the kernel source is the IO driver for the temperature and voltage monitoring on modern AMD boards. In fixing this I learnt a valuable lesson about how lm-sensors actually works. sensors looks for and reads sensor information from all the devices in the kernel that present the right interface; but you need to have the right device loaded in order for sensors to read it. So recompiling lm-sensors or re-running sensors-detect won't fix this.

Instead, you need to install the it87, or possibly the nct6775 driver at https://github.com/groeck/it87. Instructions for doing this can be helpfully found at https://linuxconfig.org/monitor-amd-ryzen-temperatures-in-linux-with-latest-kernel-modules.