Re: [lm-sensors] [PATCH] hwmon: Add driver for VIA CPU core temperature

["Michael S. Zick" <lkml@morethan.org>]

On Fri June 12 2009, Jean Delvare wrote:
> On Thu, 11 Jun 2009 15:32:55 -0700, Andrew Morton wrote:
> > On Wed, 10 Jun 2009 17:40:31 +0000 (UTC)
> > Tomaz Mertelj <tomaz.mertelj@guest.arnes.si> wrote:
> > 
> > > Harald Welte <HaraldWelte <at> viatech.com> writes:
> > > 
> > > > 
> > > > This is a driver for the on-die digital temperature sensor of
> > > > VIA's recent CPU models.
> > > > 
> > > > Signed-off-by: Harald Welte <HaraldWelte <at> viatech.com>
> > > > 
> > > 
> > > Harald,
> > 
> > You carefully removed Harald from Cc: so he probably didn't read your
> > email.
> > 
> > > I tested it on 2.6.28.3 kernel on VIA VB7002 motherboard and it does not work 
> > > correctly.
> > > 
> > > Output form sensors:
> > > 
> > > via-cputemp-isa-0000
> 
> Harald, dashes in hwmon chip names are _prohibited_. Please change to
> via_cputemp or similar.
> 
> > > Adapter: ISA adapter
> > > Core 0:       +0.0 C
> > > 
> > > On the other hand 
> > > cat '/sys/class/hwmon/hwmon2/device/driver/via-cputemp.0/temp1_input' outputs 
> > > numbers between 25-27. 
> > > 
> 
> Temperature values are supposed to be expressed in millidegrees C, not
> degrees C as it seems to be doing (although 25 degrees C seems pretty
> low for a CPU temperature?) The drivers needs to multiply values by
> 1000 before exporting them to sysfs. Then "sensors" will report the
> correct temperature value.
> 

Ah, 25 degrees C is room temperature - real hard for the junction temperature
to be 25 degrees C with power applied; lacking an infinitely perfect heatsink.

Look for an "off by one" error in shifting or masking the value.

Mike