README.Debian for lm-sensors ---------------------------- * What sensors are available on my PC? Most PC's built since late 1997 now come with a hardware health monitoring chip. This chip may be accessed via the ISA bus or the SMBus, depending on the motherboard. * What can a sensor chip do? Sensor chip usually have a few voltage inputs, usually within the 0 to 5V range. The inputs are usually in series with voltage dividers which lower the +/- 12V and +/-5V supplies to measurable range. Therefore, the readings for such inputs need to be re-scaled appropriately by software. Most chips also have a few remote temperature sensors, as well as fan speed monitoring inputs. * Is motherboard XYZ supported? lm-sensors doesn't support boards, but support chips. * Sensors detection The detection of sensor consists of several steps. All you need is to run: su sensors-detect Using first command you will become a root, second command will fire the sensors-detect utility which will guide you through the detection process. Once the modules are correctly loaded, you can run the "sensors" command to get some chip data. * The labels for the voltage and temperature readings in "sensors" are incorrect! Every motherboard is different, the inputs can be connected in various way. You can use the configuration file to describe how this measurement should be interpreted; see the comments the example file for more information. * The min and max for the readings in "sensors" are incorrect You can customize them in the file "/etc/sensors.conf". Don't forget to run "sensors -s" to write the new values to the sensors chip. * -5V and -12V readings are way out of range It's very frequent that negative voltage lines are not wired because motherboard manufacturers don't think they're worth monitoring (they are mostly unused these days). You can just add "ignore inN" lines to "/etc/sensors.conf" to hide them. Another possibility is that these lines are used to monitor different voltages. Only the motherboard manufacturer can tell for sure. Taking a look at what voltage values the BIOS displays may provide valuable hints though. * The temperatures are wrong If the temperature is -48°C, the corresponding input is not connected, check your /etc/sensors3.conf and find section, use "ignore tempX" statement to ignore this temperature source. If the temperature is negative, switching from diode input to thermistor may help. Check your /etc/sensors3.conf and find section, use "set sensorX Y" statement to change the diode to thermistor. If the temperature is too hot, switching from thermistor input to diode may help. Check your /etc/sensors3.conf and find section, use "set sensorX Y" statement to change the thermistor to diode. * My fans report exactly half/double their values compared to the BIOS The problem with much of the sensor data is that it is impossible to properly interpret some of the readings without knowing what the hardware configuration is. Some fans report one "tick" each rotation, some report two 'ticks' each rotation. It is easy to resolve this through the configuration file "/etc/sensors.conf": chip lm78-* # Or whatever chip this relates to compute fan1 2*@,@/2 # This will double the fan1 reading # -- or -- compute fan1 @/2,2*@ # This will halve the fan1 reading * Fans sometimes/always read 0 You may not have a fan with a tachometer output. Fans with tachometer outputs have at least 3 wires. Fans with only 2 wires cannot, in general, report their speed. You may need to increase the "fan divisor". For more details see the documentation in "/usr/share/doc/lm-sensors/fan-divisors" * The current value is within range but there is still an ALARM warning The ALARM indications in "sensors" are those reported by the sensor chip itself. They are NOT calculated by "sensors". "sensors" simply reads the ALARM bits and reports them. An ALARM will go off when a minimum or maximum limit is crossed. The ALARM is then latched - that is, it will stay there until the chip's registers are next accessed - which will be the next time you read these values, but not within (usually) 1.5 seconds since the last update. Reading the registers clears the ALARMS, unless the current value is still out of range. -- Aurelien Jarno Tue, 25 May 2010 11:07:04 +0200