1.\" 2.\" This file and its contents are supplied under the terms of the 3.\" Common Development and Distribution License ("CDDL"), version 1.0. 4.\" You may only use this file in accordance with the terms of version 5.\" 1.0 of the CDDL. 6.\" 7.\" A full copy of the text of the CDDL should have accompanied this 8.\" source. A copy of the CDDL is also available via the Internet at 9.\" http://www.illumos.org/license/CDDL. 10.\" 11.\" 12.\" Copyright 2025 Oxide Computer Company 13.\" 14.Dd January 11, 2025 15.Dt USMN 4D 16.Os 17.Sh NAME 18.Nm usmn 19.Nd AMD SMN user access driver 20.Sh SYNOPSIS 21.Pa /devices/pseudo/amdzen@0/usmn@2:usmn.* 22.Sh DESCRIPTION 23The 24.Nm 25driver provides the ability to read and write data from the AMD System 26Management Network 27.Pq SMN 28on AMD Family 17h 29.Pq Zen, Zen+, and Zen 2 , 30AMD Family 19h 31.Pq Zen 3 and Zen 4 , 32and AMD Family 1ah 33.Pq Zen 5 34processors. 35.Pp 36This driver is intended strictly for facilitating platform development 37and is not recommended for systems that aren't doing kernel and platform 38development on AMD Zen platforms. 39Arbitrary writes to the SMN can severely damage and destabilize the system. 40If you do not need access to the SMN, then this driver should not be 41present on the system. 42.Sh SEE ALSO 43.Xr amdzen 4D , 44.Xr zen_udf 4D 45