[src/trunk]: src/sys/arch/macppc/dev check temperatures a bit more often

[macallan <macallan%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/408232571645
branches:  trunk
changeset: 1022615:408232571645
user:      macallan <macallan%NetBSD.org@localhost>
date:      Wed Jul 28 00:59:10 2021 +0000

description:
check temperatures a bit more often
while there, explain why the delay is variable

diffstat:

 sys/arch/macppc/dev/fcu.c |  12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diffs (33 lines):

diff -r fe15527a652d -r 408232571645 sys/arch/macppc/dev/fcu.c
--- a/sys/arch/macppc/dev/fcu.c Wed Jul 28 00:36:00 2021 +0000
+++ b/sys/arch/macppc/dev/fcu.c Wed Jul 28 00:59:10 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: fcu.c,v 1.2 2021/07/27 23:38:42 macallan Exp $ */
+/* $NetBSD: fcu.c,v 1.3 2021/07/28 00:59:10 macallan Exp $ */
 
 /*-
  * Copyright (c) 2018 Michael Lorenz
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fcu.c,v 1.2 2021/07/27 23:38:42 macallan Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fcu.c,v 1.3 2021/07/28 00:59:10 macallan Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -490,7 +490,13 @@
                sc->sc_pwm = FALSE;
                for (i = 0; i < FCU_ZONE_COUNT; i++)
                        fancontrol_adjust_zone(&sc->sc_zones[i]);
-               kpause("fanctrl", true, mstohz(sc->sc_pwm ? 1000 : 5000), NULL);
+               /*
+                * take a shorter nap if we're in the proccess of adjusting a
+                * PWM fan, which relies on measuring speed and then changing
+                * its duty cycle until we're reasonable close to the target
+                * speed
+                */
+               kpause("fanctrl", true, mstohz(sc->sc_pwm ? 1000 : 2000), NULL);
        }
        kthread_exit(0);
 }