Linux 5.5 To Finally Expose NVMe Drive Temperatures Via HWMON

Linux for years has supported monitoring NVMe drive temperatures when installing the nvme user-space utility and run as root, etc. But now finally with Linux 5.5 the kernel is supporting NVMe drive temperature reporting through the hardware monitoring "HWMON" infrastructure alongside other hardware sensors.

Come the Linux 5.5 stable release in early 2020 is the NVMe HWMON support to allow reporting the current NVMe drive temperature sensor(s) and min/max thresholds via this kernel infrastructure. This in turn allows user-space to simply query the data over sysfs without the need for any utilities, no root requirement, and should gracefully work with the various programs that report HWMON sensor readings to Linux desktop users.

The NVMe HWMON support is optional via the NVME_HWMON Kconfig switch but hopefully most distribution kernels will end up shipping with the code enabled, which we don't see why they wouldn't. The code is currently staged in linux-block's next tree ahead of the Linux 5.5 merge window opening next week.

HWMON expert Guenter Roeck worked on this NVMe support code along with the support of Western Digital. Great to finally see this NVMe HWMON support happen as to not have to rely on user-space utilities running as root to read NVMe drive temperatures (yes, the next Phoronix Test Suite release will support these sensors as well alongside the existing nvme/hddtemp and other code paths for reading drive temperatures on Linux).