root/lm-sensors/trunk/prog/pwm/vt1211_pwm.8

.TH VT1211_PWM 8 "July 2008" "lm-sensors 3"
.SH NAME
vt1211_pwm \- manual control of VIA vt1211 PWM outputs

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

.SH DESCRIPTION
\fBvt1211_pwm\fP is a shell script that provides manual control of the two PWM
outputs of the VIA vt1211 Super-I/O device.

.SH OPTIONS
.TP
.B -d
Display the current settings of the two PWM outputs.
.TP
.B -i <pwm>
Initialize PWM \fB<pwm>\fP for manual control. Valid numbers for \fB<pwm>\fP
are 1 or 2. This option also writes the original vt1211 register values to
~/.vt1211_pwm\fB<pwm>\fP which is used for restoring the original settings.
.TP
.B -r <pwm>
Restore PWM \fB<pwm>\fP to the orignal settings. Valid numbers for \fB<pwm>\fP
are 1 or 2. This options reads the original settings from
~/.vt1211_pwm\fB<pwm>\fP and writes them to the vt1211.
.TP
.B -s <pwm>,<val>
Set PMW \fB<pwm>\fP output to \fB<val>\fP. Valid numbers for \fB<pwm>\fP are 1
or 2 and valid numbers for \fB<val>\fP are 0 to 255. The \fB<val>\fP range of
0-255 maps to an output duty-cycle of 0%-100%, i.e., output duty-cycle =
\fB<val>\fP * 100 / 255.

.SH 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 :-)

.SH WARNING
This script puts the PWM controller of the vt1211 into automatic mode and
toggles the thermal thresholds between extrem 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!

.SH SEE ALSO
sensors(1)

.SH AUTHOR
.PP
Juerg Haefliger <juergh at gmail.com>