I was doing this for the fourth time and munged the syntax. Here is a
copy of the thermal.c which just compiled on 7.8, with the patch.
<SNIP>
/* $OpenBSD: thermal.c,v 1.6 2019/10/08 13:21:38 cheloha Exp $ */
/*-
* Copyright (c) 2009-2011 Nathan Whitehorn
* All rights reserved.
*
* 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 AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/reboot.h>
#include <sys/sensors.h>
#include <sys/kthread.h>
#include <macppc/dev/thermal.h>
/* A 10 second timer for spinning down fans. */
#define FAN_HYSTERESIS_TIMER 10
void thermal_thread_init(void);
void thermal_thread_create(void *);
void thermal_thread_loop(void *);
void thermal_manage_fans(void);
int thermal_enable = 0;
struct thermal_fan_le {
struct thermal_fan *fan;
int last_val;
int timer;
SLIST_ENTRY(thermal_fan_le) entries;
};
struct thermal_sens_le {
struct thermal_temp *sensor;
int last_val;
#define MAX_CRITICAL_COUNT 6
int critical_count;
SLIST_ENTRY(thermal_sens_le) entries;
};
SLIST_HEAD(thermal_fans, thermal_fan_le) fans =
SLIST_HEAD_INITIALIZER(fans);
SLIST_HEAD(thermal_sensors, thermal_sens_le) sensors =
SLIST_HEAD_INITIALIZER(sensors);
void
thermal_thread_init(void)
{
if (thermal_enable)
return; /* we're already running */
thermal_enable = 1;
kthread_create_deferred(thermal_thread_create,
&thermal_enable);
}
void
thermal_thread_create(void *arg)
{
if (kthread_create(thermal_thread_loop, &thermal_enable, NULL,
"thermal")) {
printf("thermal kernel thread can't be created!\n");
thermal_enable = 0;
}
}
void
thermal_thread_loop(void *arg)
{
while (thermal_enable) {
thermal_manage_fans();
tsleep_nsec(&thermal_enable, 0, "thermal",
SEC_TO_NSEC(1));
}
kthread_exit(0);
}
void
thermal_manage_fans(void)
{
struct thermal_sens_le *sensor;
struct thermal_fan_le *fan;
int64_t average_excess, max_excess_zone, frac_excess;
int fan_speed;
int nsens, nsens_zone;
int temp;
/* Read all the sensors */
SLIST_FOREACH(sensor, &sensors, entries) {
temp = sensor->sensor->read(sensor->sensor);
if (temp > 0) {
/* Use the previous temp in case of error */
sensor->last_val = temp;
}
sensor->sensor->max_temp = 80 * 1000000 +
273150000;
if (sensor->last_val > sensor->sensor->max_temp) {
sensor->critical_count++;
printf("WARNING: Current temperature (%s:
%d.%d C) "
"exceeds critical temperature (%lld.%lld
C); "
"count=%d\n",
sensor->sensor->name,
(sensor->last_val -
ZERO_C_TO_MUK)/1000000,
(sensor->last_val -
ZERO_C_TO_MUK)%1000000,
(sensor->sensor->max_temp -
ZERO_C_TO_MUK)/1000000,
(sensor->sensor->max_temp -
ZERO_C_TO_MUK)%1000000,
sensor->critical_count);
if (sensor->critical_count >=
MAX_CRITICAL_COUNT) {
printf("WARNING: %s temperature
exceeded "
"critical temperature %d times in
a row; "
"shutting down!\n",
sensor->sensor->name,
sensor->critical_count);
reboot(RB_HALT | RB_POWERDOWN |
RB_TIMEBAD);
}
} else {
if (sensor->critical_count > 0)
sensor->critical_count--;
}
}
/* Set all the fans */
SLIST_FOREACH(fan, &fans, entries) {
nsens = nsens_zone = 0;
average_excess = max_excess_zone = 0;
SLIST_FOREACH(sensor, &sensors, entries) {
temp = ulmin(sensor->last_val,
sensor->sensor->max_temp);
frac_excess = (temp -
sensor->sensor->target_temp)*100 /
(sensor->sensor->max_temp - temp + 1);
if (frac_excess < 0)
frac_excess = 0;
if (sensor->sensor->zone == fan->fan->zone) {
max_excess_zone =
ulmax(max_excess_zone,
frac_excess);
nsens_zone++;
}
average_excess += frac_excess;
nsens++;
}
/* No sensors at all? Use default */
if (nsens == 0) {
fan->fan->set(fan->fan, fan->fan-
>default_rpm);
continue;
}
average_excess /= nsens;
/* If there are no sensors in this zone, use the
average */
if (nsens_zone == 0)
max_excess_zone = average_excess;
/*
* Scale the fan linearly in the max temperature in
its
* thermal zone.
*/
max_excess_zone = ulmin(max_excess_zone, 100);
fan_speed = max_excess_zone *
(fan->fan->max_rpm - fan->fan->min_rpm)/100 +
fan->fan->min_rpm;
if (fan_speed >= fan->last_val) {
fan->timer = FAN_HYSTERESIS_TIMER;
fan->last_val = fan_speed;
} else {
fan->timer--;
if (fan->timer == 0) {
fan->last_val = fan_speed;
fan->timer = FAN_HYSTERESIS_TIMER;
}
}
fan->fan->set(fan->fan, fan->last_val);
}
}
void
thermal_fan_register(struct thermal_fan *fan)
{
struct thermal_fan_le *list_entry;
thermal_thread_init(); /* first caller inits our thread */
list_entry = malloc(sizeof(struct thermal_fan_le), M_DEVBUF,
M_ZERO | M_WAITOK);
list_entry->fan = fan;
SLIST_INSERT_HEAD(&fans, list_entry, entries);
}
void
thermal_sensor_register(struct thermal_temp *sensor)
{
struct thermal_sens_le *list_entry;
thermal_thread_init(); /* first caller inits our thread */
list_entry = malloc(sizeof(struct thermal_sens_le), M_DEVBUF,
M_ZERO | M_WAITOK);
list_entry->sensor = sensor;
list_entry->last_val = 0;
list_entry->critical_count = 0;
SLIST_INSERT_HEAD(&sensors, list_entry, entries);
}
On Fri, 2026-05-22 at 19:43 -0400, Jeffrey S. Worley wrote:
> Context: OBSD macppc 7.6, 7.7, 7.8, 7.9
> iMag G5 (2004) (ppc970)
>
> On this single-core machine all versions of OBSD from 7.6 to 7.9
> misidentify the processor as a 900mhz model when it is much faster.
> A lowball 70C ceiling is assumed for the system, which results in the
> watchdog shutting the system down when the temp is exceeded x times
> in
> succession.
>
> The code is in thermal.c (architecture macppc)
>
> the patch is (SNIPPET)
>
> +++ sys/arch/macppc/dev/thermal.c Fri May 22 19:05:00 2026
> @@ -75,6 +75,9 @@
> if (temp > 0) /* Use the previous temp in case of
> error */
> sensor->last_val = temp;
>
> + /* FORCE THE HARDWARE PROFILE LIMIT GLOBALLY TO 80C
> */
> + sensor->sensor->max_temp = 80 * 1000000 + 273150000;
> +
> if (sensor->last_val > sensor->sensor->max_temp) {
> sensor->critical_count++;
> printf("WARNING: Current temperature (%s:
> %d.%d C) "
>
> The operative line immediately follows the /* Force the .....
> comment.
>
> After the recompiled kernel is invoked, the system won't do that
> anymore unless it gets REALLY hot.
>
> I discovered this in 7.6 and put the machine aside for a while. Last
> night I took it out, found out why, and fixed it.
>
> best,
>
> jeff (Technoid Mutant)
