Index: head/share/man/man9/Makefile
===================================================================
--- head/share/man/man9/Makefile
+++ head/share/man/man9/Makefile
@@ -121,6 +121,7 @@
 	DEVICE_SHUTDOWN.9 \
 	DEV_MODULE.9 \
 	dev_refthread.9 \
+	devctl_process_running.9 \
 	devstat.9 \
 	devtoname.9 \
 	disk.9 \
Index: head/share/man/man9/devctl_process_running.9
===================================================================
--- head/share/man/man9/devctl_process_running.9
+++ head/share/man/man9/devctl_process_running.9
@@ -0,0 +1,60 @@
+.\"
+.\" Copyright (c) 2020 M Warner Losh
+.\"
+.\" This program is free software.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd September 22, 2020
+.Dt DEVCTL_PROCESS_RUNNING 9
+.Os
+.Sh NAME
+.Nm devctl_process_running
+.Nd Returns true when devctl has a consumer process running
+.Sh SYNOPSIS
+.In sys/devctl.h
+.Ft bool
+.Fn devctl_process_running "void"
+.Sh DESCRIPTION
+The
+.Nm
+call returns
+.Vt true
+when a process has the devctl device open for
+reading, and
+.Vt false
+otherwise.
+One can assume from this that the default
+.Xr devd 8
+or similar is running when
+.Vt true
+is returned.
+Some subsystems will send a message and allow userland to do something
+before proceeding with a default action if there's a timeout.
+This call allows those subsystems to do the default action right away
+when no process is running.
+.Sh SEE ALSO
+.Xr devd 8
+.Sh AUTHORS
+This manual page was written by
+.An M. Warner Losh