Linux 5.10 Adding Support For AMD Zen 3 CPU Temperature Monitoring
The next version of the Linux kernel will allow monitoring temperatures of the upcoming AMD Zen 3 processors.
While CPU temperature monitoring support may seem mundane and not newsworthy, what makes this Zen 3 support genuinely interesting is that it's coming pre-launch... This is the first time in the AMD Zen era we are seeing CPU temperature reporting added to the Linux driver pre-launch. Not only is it coming ahead of the CPUs hitting retail channels but the support was added by AMD engineers.
Contrast that to Zen 1 / Zen+ / Zen 2 and various quirks/differences within generations, previously the support hasn't come until after launch and figured out by the community/non-AMD developers. Due to the Linux kernel cadence, at times the support hasn't been part of a released kernel until months after a CPU shipped. There has been a few times that it hasn't come until I received my review samples and then dug into figuring out the IDs or testing changes or checking for any Tctl offset in getting new CPU support added.
Thus to see Zen 3 support patches sent out by an AMD engineer prior to the launch is pleasant to see and hopefully a sign of more punctual support moving forward. But at least the code is out there pre-launch. The patch adds the new bits needed for Family 19h (Zen 3) in the k10temp driver. That patch is part of hwmon-next ahead of the Linux 5.10 merge window opening in October. Granted, due to the kernel cadence, the Linux 5.10 merge window isn't opening until early to mid October and the Linux 5.10 stable release won't be out until the end of the calendar year or so, in which case AMD Zen 3 retail CPUs will still have been shipping for weeks... So far no Zen 3 patches for the AMD_Energy driver that was recently mainlined but hopefully that isn't far behind.
Aside from thermal reporting bits and other non-critical pieces, recent mainline Linux kernel builds appear to be in good shape for AMD Ryzen and EPYC Zen 3 CPUs after various additions since Linux 5.6. Once Zen 3 CPUs are released we'll be having our usual full reports on Linux compatibility and performance. AMD recently confirmed more details on Zen 3 will be announced on 8 October.