It appears that the board designers connected all fans to the same pwm output.
Odd, but there is really no other explanation (or I don't have one).
The initial pwm_enable value if "5" means that the fan control system is in
"SmartFan IV" mode, meaning it performs automatic fan control. That mode is
controlled with a separate register and overrides all other settings, meaning
the earlier code never really changed the fan control mode at all. Which
explains why you could not set the pwm values.
Apparently, in SmartFan IV mode, you can not read the current pwm value
with that chip.
Overall I would recommend not to touch the fan control at all and leave pwmX_enable
at 5. This lets the chip handle fan control, which is better than you can ever do
manually.
One other question: Can you change pwmX_enable back to 5, and do the fan speeds
revert to the original speed if you do that ?
Thanks,
Guenter
Thank you, Guenter-
you are correct. I verified the CPU fan runs when driven off of a header with 0 PWM (case fan header that has stopped).
Odd indeed since i bought this board because it had 4 case fan headers.
In smartfan IV mode, i can read the PWM -- i just cannot write to it.
dylan@BigBox /sys/class/hwmon/hwmon2/device $ cat pwm2 pwm2_enable pwm2_mode
11
5
1
I realize that the best way for the board and CPU would be to leave pwmX_enable at 5, however I would also like a quiet computer, and the board does not take into consideration the temperature of the hard drive cages. If i use 'whisper mode', all fans turn off but the CPU fan (by fan hardware design, as you pointed out) and the drives slowly start cooking.
I will have to use the 'Generic mode', which is what i was using before.
And for the final question: Yes.
If i start in 'Whisper' mode, all fans are off (exept CPU based on fan hardware)
If i echo 1 >pwm2_enable, all fans turn on and the pwm2 sets itself to 127
If i echo 5 >pwm2_enable all fans shut back off.
Thank you very much for your time and patience.
Camden
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