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 releated information:

ATI Radeon based systems running hot since upgrades to Lucid

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.