Re: [lm-sensors] [PATCH 9/9] hwmon: (it87) Report thermal sensor type as Intel PECI if appropriate

[Guenter Roeck <linux@roeck-us.net>]

On Thu, Nov 01, 2012 at 05:37:57PM +0100, Jean Delvare wrote:
> On Thu, 1 Nov 2012 06:40:51 -0700, Guenter Roeck wrote:
> > On Thu, Nov 01, 2012 at 01:56:07PM +0100, Jean Delvare wrote:
> > > On Mon, 29 Oct 2012 10:28:30 -0700, Guenter Roeck wrote:
> > > > The BIOS, presumably. It does it on my board, but wrongly. It sets it
> > > > to 97 degrees C, while the CPU's Tcrit is 105 degrees C. I fixed the
> > > > offset to 105, and now the reported temperature matches the CPU temperature
> > > > (and moves with it). This is how I found out about PECI support in the
> > > > first place.
> > > 
> > > In which register is the PECI temperature offset value stored? I am
> > > looking at the IT8720F datasheet and I can't find it.
> >
> > On IT8728F it is in the diode zero degree adjust registers.
> > I found this from experiments; it is not mentioned in the datasheet.
> > I would guess it is the same on the other chips, though I can not test
> > it on those.
> 
> On an IT8720F chip with temp3 configured for PECI:
> 
> temp1_offset: 0
> temp2_offset: 0
> temp3_offset: -128000
> 
> I'm unsure how to interpret this -128000... This value is definitely
> not neutral, doesn't sound very realistic. I would expect a positive
> number for PECI. Maybe the offset register should be treated as
> unsigned in PECI mode? Or maybe its value is irrelevant for the IT8720F
> in PECI mode.
> 
> # grep . /sys/class/hwmon/hwmon2/device/temp3*
> /sys/class/hwmon/hwmon2/device/temp3_alarm:0
> /sys/class/hwmon/hwmon2/device/temp3_beep:1
> /sys/class/hwmon/hwmon2/device/temp3_input:25000
> /sys/class/hwmon/hwmon2/device/temp3_max:70000
> /sys/class/hwmon/hwmon2/device/temp3_min:127000
> /sys/class/hwmon/hwmon2/device/temp3_offset:-128000
> /sys/class/hwmon/hwmon2/device/temp3_type:6
> 
> This is with an it87 driver including all your recent patches. It you
> have ideas or theories, I'm interested.
> 
Hi Jean,

I agree. The alternative (+128 degrees C) sounds a bit high, though.
Maybe there is another register on IT8720F to store Tjmax ? Did you check
in the register map if there is a register value that happens to match it ?

What happens if you change the offset register value to, say, 100 ?
Does the reported temperature change as well ?

Another maybe dumb question - is this with Intel or AMD CPU ? Because
if it is AMD, it would not be PECI but AMDSI (something to fix if someone
has a system w/ IT87xx and AMD CPU).

Thanks,
Guenter

_______________________________________________
lm-sensors mailing list
lm-sensors@lm-sensors.org
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors