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Bug 142635 - /proc/acpi/thermal_zone/THRM/temperature always reports 40 C
Summary: /proc/acpi/thermal_zone/THRM/temperature always reports 40 C
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: [OLD] Core system (show other bugs)
Hardware: AMD64 Linux
: High normal (vote)
Assignee: Gentoo Kernel Bug Wranglers and Kernel Maintainers
Depends on:
Reported: 2006-08-03 04:44 UTC by Ethan Burns
Modified: 2006-10-15 12:54 UTC (History)
0 users

See Also:
Package list:
Runtime testing required: ---


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Description Ethan Burns 2006-08-03 04:44:48 UTC
My BIOS seems to report a resonable temperature in the setup, however, the OS
only reports the temp as 40 C.  

Since I am using the gentoo patched kernel, I assume that this is the place to report this bug?

bender ~ $ emerge --info
Portage 2.1-r1 (default-linux/amd64/2006.0, gcc-3.4.6, glibc-2.3.6-r4, 2.6.17-gentoo-r4 x86_64)
System uname: 2.6.17-gentoo-r4 x86_64 AMD Athlon(tm) 64 Processor 3400+
Gentoo Base System version 1.6.15
ccache version 2.3 [enabled]
app-admin/eselect-compiler: [Not Present]
dev-lang/python:     2.4.3-r1
dev-python/pycrypto: 2.0.1-r5
dev-util/ccache:     2.3
dev-util/confcache:  [Not Present]
sys-apps/sandbox:    1.2.17
sys-devel/autoconf:  2.13, 2.59-r7
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2
sys-devel/binutils:  2.16.1-r3
sys-devel/gcc-config: 1.3.13-r3
sys-devel/libtool:   1.5.22
virtual/os-headers:  2.6.11-r2
CFLAGS="-march=k8 -O2 -pipe"
CONFIG_PROTECT="/etc /usr/share/X11/xkb /var/qmail/alias /var/qmail/control"
CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/gconf /etc/java-config/vms/ /etc/revdep-rebuild /etc/terminfo"
CXXFLAGS="-march=k8 -O2 -pipe"
FEATURES="autoconfig ccache distlocks metadata-transfer sandbox sfperms strict"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude='/distfiles' --exclude='/local' --exclude='/packages'"
USE="amd64 X alsa avi berkdb bitmap-fonts cli crypt dlloader dri dts dvd dvdread eds emacs emboss encode foomaticdb fortran gif glut gstreamer gtk gtk2 ipv6 isdnlog jpeg lzw lzw-tiff mp3 mpeg ncurses nls nptl nvidia opengl pam pcre pdflib perl png pppd python qt qt3 qt4 quicktime readline reflection sdl session spell spl ssl tcpd tiff truetype truetype-fonts type1-fonts usb vorbis xml xorg xpm xv xvid zlib elibc_glibc input_devices_keyboard input_devices_mouse kernel_linux userland_GNU video_cards_nvidia video_cards_vesa video_cards_fbdev"

Any more information needed?
Comment 1 Tim Yamin (RETIRED) gentoo-dev 2006-08-07 17:00:12 UTC
The BIOS ACPI implementation looks to be broken: you might want to check if your laptop has a I2C hardware monitoring controller which should be able to report the correct temperature.
Comment 2 Daniel Drake (RETIRED) gentoo-dev 2006-10-13 19:15:23 UTC
Let's see just how broken ACPI is. Ensure that daemons such as acpid and hal are not running. Then run "cat /proc/acpi/event" and press the power button on your system. Does anything appear on the console?
Comment 3 Ethan Burns 2006-10-15 11:25:18 UTC
(In reply to comment #2)
> Let's see just how broken ACPI is. Ensure that daemons such as acpid and hal
> are not running. Then run "cat /proc/acpi/event" and press the power button on
> your system. Does anything appear on the console?

tail -f /proc/acpi/event
shows nothing when I press the power button
Comment 4 Daniel Drake (RETIRED) gentoo-dev 2006-10-15 12:02:34 UTC
You need to use "cat /proc/acpi/event", the apparent file size never changes so tail will not work
Comment 5 Ethan Burns 2006-10-15 12:34:43 UTC
eaburns@bender ~ $ sudo cat /proc/acpi/event 
button/power PWRF 00000080 00000007
button/power PWRF 00000080 00000008
button/power PWRF 00000080 00000009
button/power PWRF 00000080 0000000a
button/power PWRF 00000080 0000000b
Comment 6 Daniel Drake (RETIRED) gentoo-dev 2006-10-15 12:54:14 UTC
ok, so ACPI is working at least to some extent.

This looks like a bug in your BIOS. If you want to see it fixed, I suggest you ensure you are running the latest version and then contact the manufacturer of your motherboard or laptop.

This might be considered as a kernel bug if you can show that Windows can correctly read a true temperature through ACPI, but I think that's unlikely here and probably not worth the hassle.

If you're interested in temperature monitoring, use i2c/hwmon with lm_sensors. ACPI isn't a very good way of reading temperatures even when it does work.