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Revision 9 as of 2012-10-24 03:58:21
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Editor: penalvch
Comment: 1) Added Power Saving Tweaks section. 2) New sect. on AMD cards. 3) sudo su was only way to perform kms chg, as just using sudo: Permission denied.
Revision 10 as of 2012-10-24 16:23:18
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Editor: penalvch
Comment: Removed help wiki install instructions as using the repository driver is instruction enough.
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Certain AMD graphics cards may have better heat profiles using the proprietary AMD driver fglrx, versus the default open source ones. The Ubuntu repositories offer both [[https://launchpad.net/ubuntu/+source/fglrx-installer|fglrx-installer]] and [[https://launchpad.net/ubuntu/+source/fglrx-installer-updates|fglrx-installer-updates]]. Install instructions may be found at [[https://help.ubuntu.com/community/BinaryDriverHowto/ATI]]. Certain AMD graphics cards may have better heat profiles using the proprietary AMD driver fglrx, versus the default open source ones. The Ubuntu repositories offer both [[https://launchpad.net/ubuntu/+source/fglrx-installer|fglrx-installer]] and [[https://launchpad.net/ubuntu/+source/fglrx-installer-updates|fglrx-installer-updates]].

There are a number of causes of high temperatures and excessive fan use being reported by a systems sensors. This page intends to provide background information on how you might better isolate the real cause of the issue, to help prevent conflation of issues onto a single bug; a bug which says my machine is too hot will simply collect duplicates and me-toos and become useless. This page also aims to record known issues in this area so that the most appropriate bug can be found, these are arranged by release.

Filing a Bug

We would request that all suffers any temperature or fan related issue file a new bug and attach their machine information to it. Filing this bug using ubuntu-bug linux from a terminal window (menu item Applications/Accessories/Terminal). We can then look at these bugs and acertain whether they are duplicates of existing issues or not. Having the full hardware information for each instance greatly improves our chances of finding and fixing these issues. Once the bug is filed please ensure it is tagged kernel-therm.

Required Information

Where you believe you have a difference in thermal behaviour between two kernels or between two releases, please ensure you have your own bug and use the scripts in Monitoring System Sensors to produce logs of the temperature over time for both the before and after scenarios. Include this data with a clear description of the two test cases.

Where the issue is between releases you can use the live CDs for the previous release to attempt to recreate the before scenario.

Please ensure your bug is tagged kernel-therm.

Diagnostic Techniques

Monitoring System Sensors

Often bugs are characterised by a feeling that the machine is worse now than sometime in the past. To confirm this it is sensible to get concrete information using the system sensors.

A simple way to get a visual feel for the current temperatures is to run the following command in a terminal window (menu item Applications/Accessories/Terminal):

  • cd /proc/acpi/thermal_zone && watch grep temperature */*

This will display a constantly updating listing of your current temperatures:

  • Every 2.0s: grep temperature TZ00/cooling_mode TZ00...  Thu May 20 11:06:27 2010
    TZ00/temperature:temperature:             52 C
    TZ01/temperature:temperature:             47 C
    TZ02/temperature:temperature:             0 C

To provide a permanent record of this information you can paste the command below into a terminal:

  • ( cd /proc/acpi/thermal_zone && \
    while :; do \
      line="`date`:`grep temperature */* | awk '{ printf(\" %03d\", $2) }'`"; \
      echo "$line"; \
      sleep 10; \
    done ) | tee LOG

This will provide a log of the temperatures over time in a file called LOG. Which can be attached to a launchpad bug report:

  • Thu May 20 11:13:40 BST 2010: 051 047 000
    Thu May 20 11:13:50 BST 2010: 051 047 000
    Thu May 20 11:14:00 BST 2010: 051 047 000
    Thu May 20 11:14:10 BST 2010: 051 047 000
    Thu May 20 11:14:20 BST 2010: 051 048 000
    Thu May 20 11:14:30 BST 2010: 051 048 000

Known Issues

Below are a list of known temperature/fan related bugs with information on how to tell which bug you have and also indicating if they are fixed and if in which releases and kernel versions.


Numerous Dell systems suffering total fan failure after suspend/resume (FIXED)

526354 -- A number of Dell models suffered from total fan failure following suspend/resume. This tended to exhibit itself in one of two ways. Firstly sensor readings (see above) tended to float up from the normal around 40c level to more like 70c. Secondly under heavy load the machine would drift up to 90c or so and then power off without warning, exhibiting very high fan speeds on reboot for the first few minutes.

This issue was triggered by an embedded controller (EC) interface issue, wherein the EC would become confused following a suspend/resume cycle and no longer control the fans on our behalf. This issue was fixed shortly following the release of Lucid and contained in kernels 2.6.32-22.33 and later.

This issue is only known to affect Dell systems. The key indicator that you are seeing this bug is that fans and temperature are controlled normally until after a suspend/resume. Upgrading to the latest kernel should fix the issue.

ATI Radeon based systems running hot since upgrades to Lucid (Open)

563156 -- There are a number of reports of systems running hot, often with fans running constantly on systems with ATI Graphics. There are reports that switching to fgrlx binary graphics drivers returns fan control to normal.

To confirm this is your issue, it would be good to get temperature readings from a previous release (you can use live CD for this) and from Lucid. Also installing fgrlx binary drivers from Jockey (menu item System/Administration/Hardware Drivers) and comparing temperatures before and after would be useful. Please report back on the bug should you have this issue.

Upgrade to Lucid causes overheating, scratch re-install fixes it

583099 -- There are sporadic reports that an upgrade to Lucid (all from Karmic so far) may leave you with poor fan control but that a scratch install then resolves things. Reporter has confirmed that a karmic clean install upgraded is showing different levels of idle temperature as compared to a scratch install of lucid on the same hardware. Investigation continues.

It should be noted that between the karmic scratch install and the lucid scratch install temperature improves by 5c or about 20%. It is the upgrade which seems at times to be out of kilter.

Working around overheat

While your bug report is being addressed, one may proactively address potential overheat in the interim. One helpful tool is to monitor the hardware temperatures via lm-sensors. For more on this, please see https://help.ubuntu.com/community/SensorInstallHowto.

ASPM power management for Precise and onwards

Please be advised that as of Precise, a patch has been issued to help address overheat. For more on this, please see https://wiki.ubuntu.com/Kernel/PowerManagementASPM.

CPU governor

One may governor their CPU via the cpufreq-selector command, provided by the package gnome-applets. For example, if one had a dual core CPU, one could execute at a terminal:

sudo cpufreq-selector --cpu=0 --governor=powersave && sudo cpufreq-selector --cpu=1 --governor=powersave 

This will change your CPU setting from ondemand, to powersave. Then, you could verify the CPU governor status by executing at a terminal:


This is provided by the package cpufrequtils.

AMD Graphics Cards

FGLRX proprietary driver

Certain AMD graphics cards may have better heat profiles using the proprietary AMD driver fglrx, versus the default open source ones. The Ubuntu repositories offer both fglrx-installer and fglrx-installer-updates.

Radeon open source driver

For the radeon driver, one may perform:

sudo su
sudo echo low > /sys/class/drm/card0/device/power_profile

One may verify the new profile via:

cat /sys/class/drm/card0/device/power_profile

Increase fan speed

Dell Inspiron laptops

For Dell Inspiron laptops, one may use i8kmon to increase the fan speed. This utility is provided by the package i8kutils. For instructions on using this, please see the man page.

Power Saving Tweaks

For more power saving tweaks, please see https://wiki.ubuntu.com/Kernel/PowerManagement/PowerSavingTweaks.

General maintenance

Use a can of air to regularly blow out the dust that may accumulate in the computer exhaust area. As well, do not obstruct the exhaust areas.

Kernel/Debugging/HighTemperatures (last edited 2014-01-03 16:44:50 by penalvch)