vt1211 fan speed control

vt1211 fan speed control

[Rene Mayrhofer]

Dear lm-sensors folks, dear Mark,

I own a VIA EPIA M-6000 mainboard, whose hardware sensors are supported 
since lm-sensors 2.8.0 (vt1211) - the version I'm currently using. 
Although I still have to find a formula to get correct CPU temperature 
readings, accessing the sensor values works without a problem (I 
suspected lm-sensors to be the source of some random crashes, but can 
now rule that out).
Maybe it is a stupid question, but does the vt1211 kernel module also 
support writing to the chip registers ? During my quick skim through the 
source code, it appears that it should. But when I try to write values 
to /proc/sys/dev/sensors/vt1211-isa-6000/pwm1 (which reads 255 0), only 
the second value can be modified. After writing something there, it 
always reads 255 (0|1). Maybe I am doing something completely wrong 
here, but the feature list of the vt1211 says that it is able to control 
the speed of the connected fans in 256 steps, so (from parsing through 
the source) I figured that pwm* would be the variables to change. Is 
that supported ? Should changing pwm* work and really change the fan 
speeds ? If not, how can I make that happen (supposing that the vt1211 
fan speed control output are connected on the EPIA, but since it's also 
from VIA itself, that seems likely) ? I am willing to play with the chip 
if VIA is willing to provide a data sheet - some Windows tools like 
Speedfan claim that they are able to control fan speeds on a vt1211. 
However, I would need some pointers how to do that within the lm-sensors 
codes since I've never really looked at them in detail.

with best regards,
Rene

vt1211 fan speed control

[Mark Studebaker]

the first is the speed 0-255 and the second is the enable 0|1.
After writing a 1 to the second value you should be able to change the
first value
in subsequent writes.
You can also try the program prog/pwm/pwmconfig and see if that works.
If it does you can try prog/pwm/fancontrol.
If things don't work let us know.


Rene Mayrhofer wrote:
> 
> Dear lm-sensors folks, dear Mark,
> 
> I own a VIA EPIA M-6000 mainboard, whose hardware sensors are supported
> since lm-sensors 2.8.0 (vt1211) - the version I'm currently using.
> Although I still have to find a formula to get correct CPU temperature
> readings, accessing the sensor values works without a problem (I
> suspected lm-sensors to be the source of some random crashes, but can
> now rule that out).
> Maybe it is a stupid question, but does the vt1211 kernel module also
> support writing to the chip registers ? During my quick skim through the
> source code, it appears that it should. But when I try to write values
> to /proc/sys/dev/sensors/vt1211-isa-6000/pwm1 (which reads 255 0), only
> the second value can be modified. After writing something there, it
> always reads 255 (0|1). Maybe I am doing something completely wrong
> here, but the feature list of the vt1211 says that it is able to control
> the speed of the connected fans in 256 steps, so (from parsing through
> the source) I figured that pwm* would be the variables to change. Is
> that supported ? Should changing pwm* work and really change the fan
> speeds ? If not, how can I make that happen (supposing that the vt1211
> fan speed control output are connected on the EPIA, but since it's also
> from VIA itself, that seems likely) ? I am willing to play with the chip
> if VIA is willing to provide a data sheet - some Windows tools like
> Speedfan claim that they are able to control fan speeds on a vt1211.prog
> However, I would need some pointers how to do that within the lm-sensors
> codes since I've never really looked at them in detail.
> 
> with best regards,
> Rene

vt1211 fan speed control

[Rene Mayrhofer]

Mark Studebaker wrote:
> the first is the speed 0-255 and the second is the enable 0|1.
> After writing a 1 to the second value you should be able to change the
> first value
> in subsequent writes.
> You can also try the program prog/pwm/pwmconfig and see if that works.
> If it does you can try prog/pwm/fancontrol.
> If things don't work let us know.
I just wanted to post a quick thanks because I am probably unable to try 
this in the next few days due to other workload. As soon as I have a 
success (or failure) report, I will post it.

Many thanks for your work,
Rene

vt1211 fan speed control

[Rene Mayrhofer]

Mark Studebaker wrote:
> the first is the speed 0-255 and the second is the enable 0|1.
> After writing a 1 to the second value you should be able to change the
> first value
> in subsequent writes.
I've now tried
echo 128 1 > /proc/sys/dev/sensors/vt1211-isa-6000/pwm1
echo 0 1 > /proc/sys/dev/sensors/vt1211-isa-6000/pwm1
echo 0 > /proc/sys/dev/sensors/vt1211-isa-6000/pwm1

But cat /proc/sys/dev/sensors/vt1211-isa-6000/pwm1 returns "255 1" every 
time.

best regards,
Rene

vt1211 fan speed control

[Mark Studebaker]

it doesn't work for me either.
The VT1211 has automatic speed control, which isn't supported by the
driver.
The manual setting of PWM values doesn't appear to work.
The datasheet says the registers are RW but guess they aren't really.


Rene Mayrhofer wrote:
> 
> Mark Studebaker wrote:
> > the first is the speed 0-255 and the second is the enable 0|1.
> > After writing a 1 to the second value you should be able to change the
> > first value
> > in subsequent writes.
> I've now tried
> echo 128 1 > /proc/sys/dev/sensors/vt1211-isa-6000/pwm1
> echo 0 1 > /proc/sys/dev/sensors/vt1211-isa-6000/pwm1
> echo 0 > /proc/sys/dev/sensors/vt1211-isa-6000/pwm1
> 
> But cat /proc/sys/dev/sensors/vt1211-isa-6000/pwm1 returns "255 1" every
> time.
> 
> best regards,
> Rene