VT1211_PWM(8)

NAME
vt1211_pwm - manual control of VIA vt1211 PWM outputs

SYNOPSIS
vt1211_pwm -d | -i <pwm> | -r <pwm> | -s <pwm>,<val>

DESCRIPTION
vt1211_pwm is a shell script that provides manual control of the two PWM outputs of the VIA vt1211 Super-I/O device.

OPTIONS

-d  Display the current settings of the two PWM outputs.

-i <pwm>
    Initialize PWM <pwm> for manual control. Valid numbers for <pwm> are 1 or 2. This option also writes the original vt1211 register values to ~/.vt1211_pwm<pwm> which is used for restoring the original settings.

-r <pwm>
    Restore PWM <pwm> to the original settings. Valid numbers for <pwm> are 1 or 2. This options reads the original settings from ~/.vt1211_pwm<pwm> and writes them to the vt1211.

-s <pwm>,<val>
    Set PMW <pwm> output to <val>. Valid numbers for <pwm> are 1 or 2 and valid numbers for <val> are 0 to 255. The <val> range of 0-255 maps to an output duty-cycle of 0%-100%, i.e., output duty-cycle = <val> * 100 / 255.

REQUIREMENTS
You need root privileges to execute the vt1211_pwm script and the vt1211 kernel module needs to be loaded and you obviously need to have fans connected to the PWM outputs of the vt1211 :-)

WARNING
This script puts the PWM controller of the vt1211 into automatic mode and toggles the thermal thresholds between extreme values to fool the chip into believing that there is a temperature change and thus forcing the PWM outputs to change to the specified values. Since there is only a single PWM controller that controls both PWM outputs, setting the duty-cycle of one PWM output could affect the duty-cycle of the other PWM output. Use at you own risk!

SEE ALSO
sensors(1)

AUTHOR

Juerg Haefliger <juergh at gmail.com>