Phenom II 975 BE shows 0 celsius

Mario Lobo lobo at
Mon Aug 1 00:28:39 UTC 2011

Hi to all

In my desktop machine, I had an AM2+ ASROCK mobo with Phenom II 955 BE that 
showed each core temperature perfectly under FBSD 8-STABLE, via 
dev.cpu.x.temp. amdtemp.ko loaded.

Unfortunately this Mobo died and only found AM3 boards for which my phenom 955 
doesn't fit. So I got an ASUS M4A88T-V EVO with a Phenom II 975 BE. 

Funny thing. An AM3 phenom II fits on an AM2 board but an AM3 board doesn't 
accept an AM2/AM2+ phenom II :(.

Anyway, now, under the very same system, it shows 0 degrees on dev.cpu.x.temp 
for all cores.

I've been looking through k8temp and amdtemp src code. I am definitely not 
sure of this but I believe something might have happened to those:

From k8temp.h

K10_THERM_REG      0xa4 
K10_CURTMP(val)    (((val) >> 21) & 0xfff)
K10_THERMTRIP(val) ((val >> 1) & 1)

From amdtemp.c

 * Register control (K8 family)
#define	AMDTEMP_REG0F		0xe4

 * Register control (K10 & K11) family
#define	AMDTEMP_REG		0xa4

Output of k8temp -dn:

CPUID: Vendor: AuthenticAMD, 0x100f43: Model=04 Family=f+1 Stepping=3
Advanced Power Management=0x1f9
   Temperature sensor: Yes
 Frequency ID control: No
   Voltage ID control: No
    THERMTRIP support: Yes
   HW Thermal control: Yes
   SW Thermal control: Yes
   100MHz multipliers: Yes
   HW P-State control: Yes
        TSC Invariant: Yes

I keep a small win7 partition to test little things like this and see if the 
same thing happens there, and it doesn't, so I concluded that the sensors are 
there and are working.

One thing is worth noting though. I have used a free gadget that shows 
activity/temp for each core. It worked fine with the previous MB/CPU.That ALSO 
stopped working with this new MB. Like FBSD, it shows 0 degrees for any core 
too, although it correctly displays each core load.

The only windows tool that correctly shows the temperature are the ASUS tools 
that came with the mobo.

Other than that, everything is working fine! The only thing I had to fix was 
the fstab ada location.

I know this is not a big thing but I got accustomed to keeping an eye on those 

I have googled for a few days now searching for Thermal register address or 
offsets for the Phenom II 975 BE, or anything related to this problem and 
found nothing. Every search on AMD site was fruitless. I could not find a 
single bit of tech info on this processor there, or any other tech info for 
that matter.

Would any one have any pointers/clues/suggestions on this?

Mario Lobo
FreeBSD since 2.2.8 [not Pro-Audio.... YET!!] (99% winblows FREE)

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