USMN(4D) Devices USMN(4D)

NAME

usmn - AMD SMN user access driver

SYNOPSIS

/devices/pseudo/amdzen@0/usmn@2:usmn.*

DESCRIPTION

The usmn driver provides the ability to read and write data from the
AMD System Management Network (SMN) on AMD Family 17h (Zen, Zen+, and
Zen 2), AMD Family 19h (Zen 3 and Zen 4), and AMD Family 1ah (Zen 5)
processors.

This driver is intended strictly for facilitating platform development
and is not recommended for systems that aren't doing kernel and
platform development on AMD Zen platforms. Arbitrary writes to the SMN
can severely damage and destabilize the system. If you do not need
access to the SMN, then this driver should not be present on the
system.

SEE ALSO

amdzen(4D), zen_udf(4D)

illumos January 11, 2025 illumos