PowerMac G5 quad-core, CPU A1 DIODE TEMP: 90.8 C (for example): How to handle?

Thu Jan 15 02:37:25 UTC 2015

Context:
I got my hands on a PowerMac G5 quad-core that when the cores are kept busy (think "make -j 8 buildworld buildkernel") CPU A1's diode ends up apparently stabilizing between 90degC and, say, 91.6degC, resulting in a shutdown. (See the temperature message list below from one boot through the automatic shutdown.)

Question:
Would a temperature threshold change or a fan-operation change of some kind be appropriate to try? (If so: what and how?) Or is this likely sufficient evidence that the G5 just should not be used?

Information:

$ grep -i temperature /var/log/messages
Jan 14 01:42:29 FBSDG5M1 kernel: WARNING: Current temperature (CPU B1 DIODE TEMP: 91.6 C) exceeds critical temperature (90.0 C); count=1
Jan 14 01:42:31 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 91.3 C) exceeds critical temperature (90.0 C); count=1
Jan 14 01:42:31 FBSDG5M1 kernel: WARNING: Current temperature (CPU A0 DIODE TEMP: 91.4 C) exceeds critical temperature (90.0 C); count=1
Jan 14 01:46:21 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.6 C) exceeds critical temperature (90.0 C); count=1
Jan 14 01:46:24 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.9 C) exceeds critical temperature (90.0 C); count=2
Jan 14 01:48:21 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 93.0 C) exceeds critical temperature (90.0 C); count=1
Jan 14 01:48:23 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 95.7 C) exceeds critical temperature (90.0 C); count=2
Jan 14 01:48:25 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 95.7 C) exceeds critical temperature (90.0 C); count=3
Jan 14 01:48:26 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.9 C) exceeds critical temperature (90.0 C); count=4
Jan 14 01:49:56 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.4 C) exceeds critical temperature (90.0 C); count=1
Jan 14 01:49:58 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.4 C) exceeds critical temperature (90.0 C); count=2
Jan 14 01:50:00 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.4 C) exceeds critical temperature (90.0 C); count=3
Jan 14 01:50:02 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.8 C) exceeds critical temperature (90.0 C); count=4
Jan 14 01:50:03 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.8 C) exceeds critical temperature (90.0 C); count=5
Jan 14 01:50:06 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.6 C) exceeds critical temperature (90.0 C); count=6
Jan 14 01:50:06 FBSDG5M1 kernel: WARNING: CPU A1 DIODE TEMP temperature exceeded critical temperature 6 times in a row; shutting down!
Jan 14 01:50:07 FBSDG5M1 kernel: WARNING: Current temperature (CPU A1 DIODE TEMP: 90.2 C) exceeds critical temperature (90.0 C); count=7
Jan 14 01:50:07 FBSDG5M1 kernel: WARNING: CPU A1 DIODE TEMP temperature exceeded critical temperature 7 times in a row; shutting down!

$ uname -a
FreeBSD FBSDG5M1 10.1-RELEASE-p3 FreeBSD 10.1-RELEASE-p3 #2 r276159M: Tue Dec 23 22:25:28 PST 2014     root at FBSDG5M1:/usr/obj/usr/src/sys/GENERIC64vtsc  powerpc

GENERIC64vtsc is a GENERIC64 variant that builds both vt and sc (but not ps3).

$ freebsd-version -ku
10.1-RELEASE-p3
10.1-RELEASE-p3

(The context meets the criteria for freebsd -k to be accurate to what was in use: the default kernel name.)

$ svnlite info /usr/src/
Path: /usr/src
Working Copy Root Path: /usr/src
URL: https://svn0.us-west.freebsd.org/base/releng/10.1
Relative URL: ^/releng/10.1
Repository Root: https://svn0.us-west.freebsd.org/base
Repository UUID: ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Revision: 276159
Node Kind: directory
Schedule: normal
Last Changed Author: des
Last Changed Rev: 276159
Last Changed Date: 2014-12-23 14:56:01 -0800 (Tue, 23 Dec 2014)

$ svnlite status /usr/src/
?       /usr/src/.snap
?       /usr/src/restoresymtable
M       /usr/src/sys/ddb/db_main.c
M       /usr/src/sys/ddb/db_script.c
M       /usr/src/sys/powerpc/ofw/ofw_machdep.c
M       /usr/src/sys/powerpc/ofw/ofwcall64.S

$ more /etc/make.conf
WRKDIRPREFIX=/usr/obj/portswork
WITH_DEBUG=

$ more /etc/src.conf
WITH_DEBUG_FILES=
WITHOUT_CLANG=

$ more /usr/src/sys/powerpc/conf/GENERIC64vtsc
include GENERIC64
ident   GENERIC64vtsc

nooptions       PS3                     #Sony Playstation 3               HACK!!! to allow sc

options         DDB                     # HACK!!! to dump early crash info (but 11.0-CURRENT already has it)
options         GDB                     # HACK!!! ...
#options        KTR
#options        KTR_MASK=KTR_TRAP
#options        KTR_CPUMASK=0xF
#options        KTR_VERBOSE

# HACK!!! to allow sc for 2560x1440 display on Radeon X1950 that vt historically mishandled during booting
device          sc
#device          kbdmux         # HACK: already listed by vt
options         SC_OFWFB        # OFW frame buffer
options         SC_DFLT_FONT    # compile font in
makeoptions     SC_DFLT_FONT=cp437

# Disable extra checking typically used for FreeBSD 11.0-CURRENT:
nooptions       DEADLKRES               #Enable the deadlock resolver
nooptions       INVARIANTS              #Enable calls of extra sanity checking
nooptions       INVARIANT_SUPPORT       #Extra sanity checks of internal structures, required by INVARIANTS
nooptions       WITNESS                 #Enable checks to detect deadlocks and cycles
nooptions       WITNESS_SKIPSPIN        #Don't run witness on spinlocks for speed
nooptions       MALLOC_DEBUG_MAXZONES   # Separate malloc(9) zones

===
Mark Millard
markmi at dsl-only.net