Changeset 4251

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Timestamp:
12/03/06 11:02:09 (2 years ago)
Author:
khali
Message:

Update doc/fan-divisors.

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  • lm-sensors/trunk/CHANGES

    r4250 r4251  
    44SVN HEAD 
    55  RPM: Obsolete, removed 
     6  File doc/fan-divisors: Update 
    67  Library: Add support for the pc87247 driver (fans only) 
    78           Probe for busses before chips 

  • lm-sensors/trunk/doc/fan-divisors

    r2535 r4251  
    55try the following: 
    66 
    7 - Do you get a fan reading in the BIOS or in DOS? 
     7- Do you get a fan reading in the BIOS or using a different OS? 
    88  If not, you may not have a fan with a tachometer output. 
    9   Look and see. Fans with tachometer outputs have THREE wires. 
     9  Look and see. Fans with tachometer outputs have at least 3 wires. 
     10  Fans with only 2 wires cannot, in general, report their speed. 
    1011 
    1112- Try experimenting with the fan divisor settings: 
    …… 
    2526 64               83              21093         "" 
    2627128               41              10546         "" 
    27  
    2828 
    2929Pick a divisor so that the nominal RPM is about 50% 
    …… 
    4747-------------------------- 
    4848 
    49   Method 1: "echo x y z > /proc/sys/dev/sensors/...../fan_div" 
    50   where 'x y z' are the fan divisors for the three fans and '...' 
    51   is the sensor in question. 
    52  
    53   Method 2: Put an entry "set fanx_div y" in the appropriate section 
    54   of /etc/sensors.conf and rerun 'sensors -s'. 
    55   (x is the number of the fan 1-3 and y is the divisor). 
     49Put an entry "set fanN_div X" in the appropriate section of 
     50/etc/sensors.conf and run 'sensors -s' 
     51(N is the number of the fan, and X is the divisor you want). 
    5652 
    5753 
    …… 
    7066Thus you _increase_ the divisor if you have a slow fan. 
    7167 
    72 The drivers account for the 'fan divisor' in its calculation 
     68The drivers account for the 'fan divisor' in their calculation 
    7369of RPM. So changing the fan divisor will NOT change the 
    7470nominal RPM reading, it will only affect the minimum and maximum 
    …… 
    8783------------------------ 
    8884 
    89 This is caused by a fan clock which is actually half the expected 
    90 22.5 kHz, or by a fan which outputs twice as many pulses per revolution 
    91 as expected. 
     85This is rare, but can happen. This is typically caused by a fan which 
     86outputs 4 pulses by revolution, instead of the standard 2. 
    9287 
    9388As we learned above, you can _not_ fix this by changing 
    …… 
    9590section of /etc/sensors.conf: 
    9691 
    97         compute fan1  @/2,  2*@ 
    98         compute fan2  @/2,  2*@ 
    99         compute fan3  @/2,  2*@ 
     92        compute fanN  @/2,  2*@ 
    10093 
     94(N is the number of the fan) 
    10195 
    10296